Wikipedia:Reference desk/Archives/Computing/2008 November 29

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November 29

OS X mail application

I've been using Mail.app for e-mail on my OS X machine for ages now but it's been driving me a little batty. Basically it doesn't have any ability to do an "advanced search" -- I can either search by to field, from field, subject field, or entire message. What I want is something quite simple, like search entire message by only those with the right from field (there are a few people in my life who send me a ton of e-mail).

So I've been thinking about alternative approaches. One is to set up a smart mailbox for each of those people who send me a lot of e-mail, and use that as a way of sorting out things (I can limit searches by a given folder). Another is to get another mail client, like Thunderbird. I've never used Thunderbird before, and would want to make sure it could do this. I've searched around a bit and it seems like Thunderbird has more advanced search possibilities but nothing as simple as a single "advanced search" screen like one expects out of search engines. Is this correct?

(I'm so frustrated with mail applications in part because I receive maybe 20 e-mails a day, aka 140 a week or 560 a month, and keeping track of all of them in a major, major issue, and yet the ability to search and sort them is so rudimentary on most of them that I've seen...) --98.217.8.46 (talk) 01:02, 29 November 2008 (UTC)

This is not a solution, but what I have been doing with a similar (but in a MUCH smaller scale) problem of mine is that I rank messages by name of the sender. I have been using Mail as an IMAP client and find it satisfactory for my small-scale use (ALL mailboxes combined have less than 11k messages right now). HTH, Kushal (talk) 14:15, 29 November 2008 (UTC)

Having written all that out I thought I'd try the "Smart folders". They work OK for what I want, in terms of being able to find old messages. They don't really help me stem the tide of things in general (it is still very hard to manage the information flow) but they help for making sense of those few high-volume people. --98.217.8.46 (talk) 17:44, 29 November 2008 (UTC)

Thunderbird has a search window where you can add several criteria and use "AND" or "OR" (but not some AND and some OR) - on my system it's under Edit-Find-Search Messages. I also know some people like to use Gmail because of its simple yet powerful search and "tag" system. Gmail can import messages from other accounts and also use their address when sending. Jørgen (talk) 19:20, 29 November 2008 (UTC)

Since all Mail messages are Spotlight indexed, you can search for mail using advanced Booleans in the spotlight window (and then save a Smart search folder using that criteria). Also check out HoudahSpot [1] which takes Spotlight searches to the next level. --70.130.54.91 (talk) 06:11, 30 November 2008 (UTC)

Questions about /etc/init.d/network

Greetings. I have a question about the following section of the network script located in /etc/init.d/network, which I am sourcing from a CentOS system.

interfaces=$(ls ifcfg* | \
LANG=C sed -e "$__sed_discard_ignored_files" \
-e '/\(ifcfg-lo\|:\|ifcfg-.*-range\)/d' \
-e '/ifcfg-[A-Za-z0-9\._-]\+$/ { s/^ifcfg-//g;s/[0-9]/ &/}' | \
LANG=C sort -k 1,1 -k 2n | \
LANG=C sed 's/ //')

While I know the final output of this command, and the resulting variable is 'eth0' and 'eth1' on seperate lines, I am unsure if I exactly grasp what it is trying to do, specifically the regular expression parts. The following is what I grasp from using portions of the command within a shell, however as mentioned before, I am unsure exactly what the regexp portions do.

• LANG=C sed -e "$__sed_discard_ignored_files" - Discards files containing extensions specified within the environment variable which was created when /etc/init.d/functions runs (~, .bak, .orig, .rpmnew, .rpmorig, .rpmsave)
• -e '/\(ifcfg-lo\|:\|ifcfg-.*-range\)/d' - Discards the loopback interface file, and anything with 'ifcfg-' any single character, and '-range'.
• -e '/ifcfg-[A-Za-z0-9\._-]\+$/ { s/^ifcfg-//g;s/[0-9]/ &/}' - Outputs a list of the interface files, in the format "eth #" where # is the interface number
• LANG=C sort -k 1,1 -k 2n - sorts the list with a key starting and ending at 1, then at 2n (at least that's what the manual page for sort says), though in my experimentation, this didn't change the resulting list at all.
• LANG=C sed 's/ //' - Removes the space from "eth #", so it outputs "eth#"

Do I have at least a ruidamentary idea of what these bits are doing? And if possible, might I inquire what the regular expressions are actually doing? Many thanks! ~Sincerely, Dani 137.155.2.27 (talk) 08:15, 29 November 2008 (UTC)

Well...

• The ".*" in the 2nd sed means "0 or more of any character", not "any single character", so /ifcfg-.*-range/ matches anything containing "ifcfg-" and "-range"
• The 3rd sed:
  • is limited to lines matching /ifcfg-[A-Za-z0-9\._-]\+$/, which is any line with "ifcfg-" followed by at least one character out of upper- and lower-case letters, digits, '.', '_', and '-'. That's a pretty inclusive set; maybe it's to ignore lines with spaces in?
  • s/^ifcfg-//g removes the "ifcfg-" (if it's at the beginning, which none of the other regexes have checked for)
  • s/[0-9]/ &/ inserts a space before any digit (substitutes anything matching /[0-9]/ with a space followed by the string matched); this is so that it looks like a different "field" to the sort command
• The sort command looks a bit messed up to me, but what do I know? I think it's trying to sort numerically by the second field - so the "1" in "eth 1" - but that would just be sort -n -k2, or sort -nk2
• The final sed just strips out the space that was put in to make the sort work.

Looks incredibly convoluted for the job to me, but without seeing the directory list it's working on, it's hard to know exactly how to simplify it and keep it working for everyone's system... - IMSoP (talk) 19:47, 29 November 2008 (UTC)

Auto complete data

Where are all the data that are automatically filled in computer forms saved in a computer? —Preceding unsigned comment added by 120.89.115.99 (talk) 18:17, 29 November 2008 (UTC)

That depends on the browser you are using. Most modern browsers will keep it within a configuration folder, normally located within your user's application data folder. --Sigma 7 (talk) 19:21, 29 November 2008 (UTC)

Relative vs. Absolute referencing

Is there any way to reference files and foldres address i.e. paths in a relative way ? —Preceding unsigned comment added by 120.89.115.99 (talk) 18:20, 29 November 2008 (UTC)

Are you referring to URLs? If so, I know you can move up a folder or two from an address by typing two dots after a slash: /.. for one level and /../.. for two, just like you would in BASH: cd ../.. or in the Windows command prompt: cd ..\..--Rjnt (talk) 18:30, 29 November 2008 (UTC)

You may also be able to use logical variables defined at the O/S level, like "$WIBBLE_DIR/wibble_executables_subdir". StuRat (talk) 18:54, 29 November 2008 (UTC)

In what context? I know it from html, where relative referencing means relative to where the html file is located. So if you want to link to /z/lyrics/kevin_bloody_wilson/kevin's_court_song.html in an html file that is located under /z/lyrics, then it can be referenced with href="/kevin_bloody_wilson/kevin's_court_song.html". If the file is under /z/dirty_pictures, you could access it with href="../lyrics/kevin_bloody_wilson/kevin's_court_song.html", which first goes up one directory (the two dots that Rjnt mentioned) and then down from there. I hope I got the grammar right, because I'm a bit rusty. Why don't we have an article on relative referencing? DirkvdM (talk) 18:58, 29 November 2008 (UTC)

... presumably because its not called "relative referencing". -- Fullstop (talk) 04:10, 4 December 2008 (UTC)

Setiing up a lan with two Suse machines

For a quick answer, skip to the bottom, after the underlined "I got NFS to work as well!"

I want to set up a local network, but can't get find much info on that.
First the basics: I have a pc and a laptop (netbook), both running Suse (11.0 and enterprise desktop 10, respectively), wich are connected with ethernet to a Linksys (wireless) router, which in turn is connected to a modem. Both can access the internet, so that's ok.
This being Linux, I sort of expected it to work instantly. I looked up the address of the netbook in the router and tried to surf there, but Firefox says "Failed to Connect. The connection was refused when attempting to contact 192.168.1.113. Though the site seems valid, the browser was unable to establish a connection." Then it suggested firewall settings might be to blame, so I disabled that on both machines and the router (of course not permanently, just to start with as many obstacles as possible out of the way). That didn't help.
So I searched for more info and found that I had to set certain things in yast > network settings / network card (differs on the two machines). On both machines, I set ifup instead of networkmanager, two separate host names, the same domain name, use dhcp, write hostname to /etc/hosts, activate device at boot time and firewall: external zone. Most of that was already set and most of the rest remained empty. I assumed it was the different domain names that were to blame, so I tried again.
However, the result is the same. Note that when changing from networkmanager to ifup on the netbook, it complained that it could not access installation media, so I skipped two files (from ///usr/share/lang, so I don't think that was important). Another thing is that the netbook has a rather odd device name: eth-id-00:21:85:4f:32:1c, where I expected a simple eth0. When I execute ifconfig, I get a normal eth0, with the 00:21:85:4f:32:1c as HWaddr. So just a different presentation, I presume.
So what am I doing wrong? DirkvdM (talk) 18:42, 29 November 2008 (UTC)

I'm no expert at all, but could the error be that you haven't set up a web server? You say you try to "surf to" the computer, but how does the computer know what to show to the web browser? Have you tried to ping it? (then you'd have to set up file sharing if ping works, I have no idea how to do that on Linux but I'd be surprised if it was difficult) Jørgen (talk) 18:52, 29 November 2008 (UTC)

Good question. A ping from the console gives a repeated line with "64 bytes from 192.168.1.113: icmp_seq=<climbing number> ttl=64 time=0.167 ms", with the time varying around 0.2 ms. A ping from the router gives the same, except with a much slower time of 0.9 ms (surprisingly). In both cases 0 packets lost. I can also do a traceroute in the router, which apart from two administrative lines (30 hops max, 40 byte packets) gives only one line, with three timings around 1 ms. As for 'surfing to the computer', I can also do that with my own computer by surfing to / (root). So I imagined the same would work with another computer if I have its address. DirkvdM (talk) 19:17, 29 November 2008 (UTC)

Dirk, I love linux, and don't particularly enjoy going linux-bashing, but your statement "this being Linux, I sort of expected it to work instantly" in the context of wireless networking, gave me quite a a belly muscle excercise. My knee-jerk answer would be try a wired connection first, but if both computers can access the internet, wired vs wireless shouldn't be the issue. You write ..."and tried to surf there, but Firefox says"..., but as Jørgen points out, you can surf only to websites that have a web server running on the target computer, and you haven't written anything about installing one. I suggest that you install ssh (client and server) on both computers, and try to log into one of your computers from the other using ssh.

Regarding the installation media problem, I have no experience with Yast, but if it complains about not being able to access installation media, I suppose there is a configuration file somewhere that says where Yast should fetch new packages. If that file refers to both CD's and web-based repositories, I would try commenting out the references to the CD's, to force it to immediately go to the web-based repository. --NorwegianBlue ^talk 21:04, 29 November 2008 (UTC)

I am trying a wired connnection. It's a wireless router, but note I say 'connected with ethernet' and I'm talking about eth0. Maybe I should have been a little clearer about that. And I sort of expected it to work instantly because networking is the area Linux is best in, I understand. For example, it sets up an internet connection while installing itself and I understand that with Ubuntu you can even start surfing to find help on the installation process - very handy! Anyway....

Both machines have openssh installed. I understand it's text-based (and I'm no hero in that area). So I type that in and then in the list I see ssh needs a hostname, but when I fill in the hostname I gave the netbook ('Netbook', very originally) I get "name or service not known". All the rest are options. Do I need any of those? Such as [-p port]? I haven't a clue.

But is there no other way? Reading the ssh article - it appears to be developed for secure connections. But I don't need that; I basically want the two computers to act like one. So open a program on the one and then with that open a file on the other? Just like I access a cd or a memory stick (or hd or memory, for that matter)? Why would it have to be different when it's over ethernet? DirkvdM (talk) 09:08, 30 November 2008 (UTC)

ssh is invoked like this:

dirk@Desktop:~$ssh Netbook

I assume your username is the same on both machines, if it isn't ssh needs a username argument:

dirk@Desktop:~$ssh -l DvdM Netbook

If the following conditions are satisfied:

1. both machines can access the internet
2. /etc/hosts is set up correctly,
3. the ssh daemon is running,
4. the router is not doing something weird,

Then this really should work. You have already confirmed condition 1. To check if there is a problem in /etc/hosts, check if this works:

dirk@Desktop:~$ssh 192.168.1.113

I'm assuming 192.168.1.113 is the ip-address of your second computer. (To make sure, type 'ifconfig' on the command line, you'll some lines of output, one of these shows the ip address of the computer). To check if the ssh daemon is running type

ps -e | grep sshd

You should get at least one line of output, that ends in "sshd". If you don't, make sure that you have installed both openssh-server and openssh-client.

The error message you quote from firefox is a bit suspicious. It says that the connection was refused. When I browse to an address that doesn't have a web server running, I get the error message "Unable to connect. Iceweasel can't establish a connection to the server at 127.0.0.1." (Iceweasel is firefox under another name). This could indicate that it is the router that somehow is blocking the connection. I have a Linksys router too, and I see that it has a setting (in the "security" tab) called "Filter Internet NAT Redirection", which is explained as follows: "This feature uses Port Forwarding to prevent access to local servers from your local networked computers." It is unchecked in my router, and I have never tried to see what happens if it is checked, but judging by the description, it sounds like something which could cause problems like those you experience.

ssh is usually quite hassle-free, and I wouldn't recommend changing to some other login mechanism. However, ssh won't make the two computers behave as though they were one. It sounds like what you want to do is to mount directories of the remote computer on the filesystem of your local computer. I believe this can be done, but I haven't tried it, and hope someone else comes along, to explain how that is done. But, for the sake of diagnostics and making sure your setup is ok, you really should get ssh working before proceeding. --NorwegianBlue ^talk 13:58, 30 November 2008 (UTC)

I also thought about somehow mounting the partitions of one computer on the other, but didn't know how until I stumbled upon NFS, which appears to do that. And indeed it seems to work! Well, it might if the mount would not have been owned by root and I can't find a way to open a root browser to change the permissions. Aaaargh! A problem I encountered several times before: how do I open a program as root? Anyway, as you say, I should be able to get ssh working too.

"ps -e |grrep sshd" gives a line on the pc (3120 ? 00:00:00 sshd), but not Netbook. But on Netbook in software management I see that openssh is installed, and the summary says "secure shell client and server (remote login program)", so that seems to be ok. When I look for sshd it gives no results. Is that a problem? When I try it the other way around, from Netbook to the pc, after a minute or so I get "ssh: connect to host 192.168.1.103 port 22: Connection timed out".

Btw, what do I get when I get ssh to work? Do I get to control the other machine from the command line? Like I said, I don't know my way around that. And the things I do know take forever, even though I can type blind fairly fast. By the time I have gone down 10 levels in the dir hierarchy I've forgotten what I was looking for. :)

Still, for completeness: The user names are not entirely the same on both machines; on Netbook it's not capitalised. But neither 'ssh dirk@Netbook' nor 'ssh -l dirk Netbook' works. In both instances I get "ssh: Could not resolve hostname Netbook: Name or service not known". When I try the ip address, I get "ssh: connect to host 192.168.1.113 port 22: connection refused". And in the router, the 'filter internet NAT redirection' is not checked. The other three on that page are. DirkvdM (talk) 18:57, 30 November 2008 (UTC)

(outdent)

I'll answer your questions as systematically as I can. Quotes from your previous posts are in italics:

Regarding the ssh daemon on the target machine: When I look for sshd it gives no results. Is that a problem?

• If "ps -e | grep sshd" on the netbook gives no output, that is indeed a major problem. If sshd is not running on the host (Netbook), ssh from the desktop won't be able to make a connection. I'm puzzled that it isn't running when it is installed. To force it to start, you would type "/etc/init.d/ssh start" on a Debian-based distro. I don't know if it's the same in suse.

How do I open a program as root?

• From the command line:

su # su will prompt you for root's password, and you'll be logged in as root
then type the name of the program, with a complete path if necessary.

Alternatively

sudo programname_with_path_if_necessary # provided sudo is installed.

I don't know what the xauth setup in suse is like, but you might get problems with gui programs using the first method, and not with the second. If you run into problems with the display not being accessible, the easiest solution is to install sudo if it isn't installed, add your username using visudo (copy the permissions of root), and use the second method.

When I try it the other way around, from Netbook to the pc, after a minute or so I get "ssh: connect to host 192.168.1.103 port 22: Connection timed out".

• This one has me stumped. It indicates that the address is valid (otherwise you would have gotten the error message "no route to host"). It also indicates that sshd is running (otherwise you would have gotten "connection refused"). You have also confirmed on the target computer that sshd is running. What you should be seeing, is a prompt for the password of the username that sshd on the target machine thinks you are intending to use. Since there is a difference in usernames, remember the -l option. But even if you try to log into an account that doesn't exist, you should be prompted for a password.

Btw, what do I get when I get ssh to work? Do I get to control the other machine from the command line?

• Yes, exactly.

Regarding the differences in user names: The user names are not entirely the same on both machines; on Netbook it's not capitalised. But neither 'ssh dirk@Netbook' nor 'ssh -l dirk Netbook' works.

• To keep the number of things that could go wrong to a minimum, I would stick with ssh -l correctly_capitalized_username_on_target_machine ip-address.

You write (when connecting from desktop to Netbook): In both instances I get "ssh: Could not resolve hostname Netbook: Name or service not known".

• Please doublecheck /etc/hosts on the desktop machine. The error message says that the desktop is unable to translate the name Netbook into an ip-address. And as said above, stick with ssh'ing to the ip-address until at least that works.

Regarding router settings: And in the router, the 'filter internet NAT redirection' is not checked. The other three on that page are.

• That is the same setup that I have.

Regarding "browsing" to the target computer, you wrote : Well, it might if the mount would not have been owned by root and I can't find a way to open a root browser to change the permissions. And above: As for 'surfing to the computer', I can also do that with my own computer by surfing to / (root). So I imagined the same would work with another computer if I have its address.

• If you type "ftp://192.168.1.113" in the address bar of firefox, you should get a prompt for your username and password on the netbook. If /etc/hosts were setup correctly, "ftp://Netbook" should have the same effect. root access using this method might be disabled, but you should be able to log in with your ordinary username. You will then see the files of your home directory (and its subdirectories) only, not the root directory. You can get around that by creating a softlink to the root directory in your home directory. However, mounting the filesystem is probably what you want to achieve. AFAIK there are three methods, NFS, Samba and sshfs, but as I wrote above, I haven't tried this (although I have made a directory tree on my linux server accessible from the windows machines in my network using Samba).
• When you write that NFS appears to work, but that there is a problem with permissions, what exactly is happening? Are you able to mount the filesystem on the netbook as read-only? And which username on the remote computer (netbook) are you using?

Regrettably, linux programs don't always work out of the box, but ssh using a wired connection is one of the things that really ought to work. There appears to be at least three issues: (1) your desktop is unable to translate "Netbook" to the correct ip address. (2) sshd is not running on the netbook. (3) something is blocking the ssh connection from the netbook to the desktop. The last one is what's bothering me most. That same "something" might also block the connection the other way once you sort out the other issues. I can think of only two possibilities, a router setting, and a software firewall. Here (ubuntu) and here (suse) are threads that discuss similar problems, that might be helpful. --NorwegianBlue ^talk 22:27, 30 November 2008 (UTC)

If all I get with ssh is a command line, then it is not for me, I suppose. Still, I can't stand it when something doesn't work, so I tried a little more. Here's the results, but if that doesn't give you a clear hint, then let it be. I'll try NFS instead.

When I said that when I look for sshd I get no results, I meant in the software manager. That that gave no results is odd, since 'which sshd' (one of the commands I remember because it can be extremely helpful) gives me /usr/sbin/sshd (and ssh is in /usr/bin/ssh, so without the 's'). So it is installed, but the software manager does not know about it?? Anyway, I typed '/usr/sbin/sshd start', which results in 'Extra argument start'. No idea if that is good or bad. So I tried the ssh command with the other machine's ip address on both machines, but with the same results.

On both machines, in the network settings, 'write Hostname to /etc/hosts' is checked (which was the default). On both, in etc/hosts I don't see 192.168.1.1x3 (or anything like it) and the machine's name only in the last line, behind the address 127.0.0.2 (actually two entries there, the other being the machine name followed by a dot and the group name (which of course is the same on both machines)). So I tried connecting to that ip address (I know nothing, so I'll try anything), but now the connection is refused.

When I try ftp, on the pc I get "Failed to Connect. The connection was refused when attempting to contact 192.168.1.113." And on Netbook the connection times out.

About starting a gui as root from the command line - I already tried that by typing 'Konqueror' in a root console, which didn't work. And when I look for it with 'which Konqueror' it tells me it can't find it (in the standard paths). But it is installed. What I really want is to be able to switch to root within Konqueror. In 'properties > share' there is an option to login as root, but that doesn't work. And now the computer freezes on me. This is the sort of thing that made me switch to Linux (never crashed on me once in three years, except for X once or twice), but strange things happen with this computer. Either this Suse version (enterprise desktop) or the computer is buggy. I hope it's the former, so I can install a better version, but fear it's the latter.

Anyway, with NFS, I can view everything on the pc now, but it is mounted as root. Ah, of course, I ran the whole thing as root, so I should have done that as a normal user. Silly me. But I'm very tired now (been a very long day at work), so I'll do that first thing tomorrow. Thanks for your patience with me so far. :) DirkvdM (talk) 20:08, 1 December 2008 (UTC)

First, yes - ssh does give you a command line, but it does a lot more behind the scenes in various protocols, to make connections work smoothly. I definitely recommend not giving up. The problems you experience do not suggest a "buggy" machine to me (i.e. a machine with deficient hardware). These are setup problems, and to use linux efficiently, you need to be able to handle such tasks, even when they involve a little command line work.

I'm not familiar with software management on Suse, but you need to make sure that the ssh server is installed and running. Google found this, which to me suggests that it needs to be installed and/or configured in your setup. If the software manager of Suse is anything like its gui counterpart in Debian-based distros (Synaptic), then searching for a package name will show it, with an icon indicating whether it is installed or not. The package containing sshd is called openssh-server, not sshd, at least in Debian. Googling also tells me that there is a software firewall in Suse, and I strongly suspect it to be the culprit when a connection is refused an attempt to make a connection times out. The second link in my previous post gives (hopefully correct) instructions as to how to make sure ssh connections are allowed in Suse. Here is another link that appears to be relevant to your problems. It says that you start sshd in Suse simply by typing its name, without any arguments. Thus the "start" argument was superfluous, hence the error message. And it doesn't take ip-address arguments, it sits there and waits for incoming connections. That's the sort of thing daemons do.

If there's no mention of the 192.168.1.1x3 guys in /etc/hosts, there's simply no way you can access the other computer by its name. There may be a menu-driven way to do this, but the easiest thing to do would be to edit /etc/hosts by hand. Easy - that is - if you use a console based text editor (like vi, emacs or nano). You'll need to be root, and will probably run into the x-authority hassle I referred to above if you try to start a gui editor like kwrite as root. You can probably get around that by using sudo if that is installed, se above. (A google search for disable xauth gives 35,000 hits - on a secure network xauth is a true PITA).

Your /etc/hosts file needs to contain lines similar to these, taken from the /etc/hosts of my desktop (pluto):

127.0.0.1	localhost
127.0.1.1	pluto.Mydomain  pluto
192.168.3.49	atlas.Mydomain  atlas

127.0.0.1 is the loopback virtual network interface, a generic ip-address that your computer can use to access itself. The second one, 127.0.1.1, is something similar, as is your 127.0.0.2. It is the line beginning with 192.168.3.49 that tells the desktop that atlas (my server) is a synonym for 192.168.3.49.

Regarding "which Konqueror" failing, linux is case-sensitive, remember? And I'm pretty sure konqueror shouldn't be capitalized. Try "which konqueror", and I expect you will find it, probably in /usr/bin.

Hope this helps! Don't give up. --NorwegianBlue ^talk 22:14, 1 December 2008 (UTC)

(alternating indent)

On the pc, yast has an sshd server configuration, but on the netbook it hasn't. Also, many things work differently on the netbook, which can be very confusing. Yet another reason to do a new installation. But it has no dvd player, so I'd have to buy an external one first. Or install from hd, which brings me back to copying from the pc. Possibly with NFS But first look at ssh once more.

In sshd configuration on the pc, 'supported ssh protocol versions' is set at '2 only', which I changed to '2 and 1', as on the page you linked to. The rest is the same as on that page.

I am sure I had stopped the firewall on both machines and the router, but now it is active again on the pc. So disabled it and tried again. Now I get "The authenticity of host 192.168.1.103 can't be established" Then it tells me the rsa fingerprint and asks me if I want to continue. So sort of a snag, but it seems to work. To see what was the cause, I say no, change ssh protocol to '2 only' and try again. And I get the same. So it was the firewall? I'm very sure I disabled it. Except I did that not in yast's 'security and users > firewall' (as I did now), but in the network card setup. Are there two firewalls or do the two entries conflict (which would be stupid, although I've seen something like that before)? Ok, so now I do 'ssh 192.168.1.103' again and say 'yes' and then it tells me it permanently added that address to the list of known hosts, but then 'write failed: broken pipe' and back to the prompt. Damn.

You're right, I should have written 'konqueror' without capitalisation. So now I can find its location and start it. But then it turns out it is mounted read-only, which means I can't change ownership, but also not permissions. Not even as root!? I suppose I need to change fstab, but I'm only vaguely familiar with that. The relevant line consits of source dir on the pc, the mount point and then 'nfs defaults 0 0'. How do I change that to mount it as a normal user ('dirk')? Or do I need to do that in some other way?

This very simple operation (or such I imagined it would be) has now consumed many hours of my precious time (almost two full days now) - I also try to lead an offline life (no, really), and I have quite a lot of things to do recently (such as shopping now if I want to eat this evening :) ). So I'll have to leave ssh (for now) and use NFS. Could you help me with this last bit? (which I hope it will be). DirkvdM (talk) 13:33, 2 December 2008 (UTC)

Damn, I thought I had it. http://www.troubleshooters.com/linux/nfs.htm looks very handy. I haven't read it completely yet (and it's too late to do that tonight and tomorrow I'm working), but it seems that all that is needed is /etc/exports on the server and /etc/fstab on the client. So in the former (on the pc) I changed 'ro' to 'rw' and to make sure restarted it and on the netbook switched to root (log out and back in - first time I found a use for that) and executed mount -a. Then I tried to change ownership for the dir mounted over nfs. But still I don't have permissions to do that. Btw, I should change to user 'dirk' and group 'users', right? Not that that matters yet, because I get 'access denied'. Hold on, I can't get even view anymore. That is, I can view the dirs directly under the mount point, but no further down. All firewalls are down, so that's not it. I can't think of anything that is different from when I viewed them before except the change in /etc/exports on the pc. Oh, headache....

Btw, I had a look at your userpage and now you're NorwegianPurple. :) DirkvdM (talk) 19:33, 2 December 2008 (UTC)

(ec: I wrote the paragraph below before reading your last post, the old version of the page must have been cached)

Well, at least now we have a complete diagnosis:

• The reason why you couldn't connect from the PC to the netbook, was that there was no ssh server on the netbook.
• The reason why you couldn't connect from the netbook to the PC, was that the connection was blocked by the PC's firewall.
• In addition, you couldn't connect using the names that you had given your machines because these had not been written to /etc/hosts.

The first time you connect to a new host with ssh, you get the message "The authenticity of host 192.168.1.103 can't be established", you're shown an rsa fingerprint, and are prompted whether you want to continue. This is normal behaviour. If you are making a connection between two of your own PC's you can safely answer yes. The client then saves this information about the host, and uses it as part of the verification process when subsequent connections are made. If everything works when you use ssh protocol 2 only, this is the safest setting (see the article).

I googled error the message 'write failed: broken pipe' in the context of ssh, and found two suggestions: (1) you have permitted ssh connections in the firewall on the PC, but not in the firewall on the netbook. (2) Using ssh protocol 1 (or "1 and 2") might resolve this issue.

You repeat that the netbook has no dvd player, and that this prevents you from installing packages. I addressed this above when I wrote: I have no experience with Yast, but if it complains about not being able to access installation media, I suppose there is a configuration file somewhere that says where Yast should fetch new packages. If that file refers to both CD's and web-based repositories, I would try commenting out the references to the CD's, to force it to immediately go to the web-based repository.. Did you try that, and if so, what happened?

I'll comment mounting of an NFS disk on your talk page.

--NorwegianPurple ^talk 20:26, 2 December 2008 (UTC)

GOT IT! Well, sort of. A new thing I tried (leaving out as many things as possible that can get in the way) was to make a direct connection, without the router. I also logged into the netbook as root to avoid permission problems. And when I type 'ssh 192.168.1.103' I get prompted for the password. I used the root password (because I specified no user) and I'm in! At least I can surf around the hd's. But now comes the problem I mentioned earlier: I have precious little experience with the command line. Only system administrative work. I tried viewing a text with '/usr/bin/firefox lamp.html', upon wich I get 'Error: no display specified'. So I tried a copy with 'cp lamp.html /home/dirk', but of course that refers to the pc, not the netbook. So why did I not get an error, without a capitalised 'd'? Well, I forgot the trailing slash, so now I have a copy of that file under /home with the new name 'dirk'. Which goes to show my point. I know enough to figure this out, but with my lack of knowledge even the few things I know how to do I still do wrong. And I really don't have the time now to learn working with the command line. As long as the grammar is logical I can figure it out (that's what I'm good at in general), but I lack everything but the most basic knowledge.

In the ssh man file I read something about X11 forwarding, which I don't follow. Can I access the remote computer with a gui using this?

But one thing I really want to know now, even if nothing else works, is how to copy from the pc to the netbook (and later vice versa, I suppose). That would help me a lot. Now that I'm logged into a remote computer, how do I refer to the computer itself? I tried 'cp lamp.html 192.168.1.113/home/dirk' and the same with 127.0.0.1, but neither works (cannot create regular file .... no such file or directory).

Btw, I also tried 'ssh -l Dirk 192.168.1.103' after I logged out and back in as a normal user and that works. So I won't have access problems after I have copied files.

ftp://1092.168.1.103 still doesn't work. Nor with just plain the address (the very first thing I tried)

Inserted by NorwegianBlue: There's a typo in the url above, but I'm sure you typed the correct address when trying this out. --NorwegianBlue ^talk 19:59, 4 December 2008 (UTC)

And now something astounding. I sometimes try something I know won't work, but then what do I know. I made the connection through the router again, with the remote login open, and tried navigating though the pc. And it works! So somehow the router gets in the way of setting up the connection, but not after that. Weird. Or is it?

Exciting new attempt: set up the firewall on the router. Still works. Firewall on the pc back up. Still works. I even started the firewall on the netbook for the first time. And it still works. Next test: close the connection and try again. Damn, doesn't work. Times out. Anyway, I can make a connection, even if it's not in the most convenient of ways. And that's the main thing.

Lunchtime. I'll look at my user page for what you wrote about NFS in an hour or so. DirkvdM (talk) 10:40, 4 December 2008 (UTC)

• I'll be back later tonight, but just a clarification: you wrote: "I made the connection through the router again, with the remote login open, and tried navigating though the pc. And it works!". I didn't understand exactly what you did. Did you unplug and replug some of the wires, or what? Could you please have a look and doublecheck which wire goes where, and explain exactly what your setup looks like? I imagined it was something like this, the names in parentheses are the labels on the connections on the router:

                               Linksys router
                              +-----------------------+
 broadband_connection ------> |(uplink)               |
                              |                       |
 PC 192.168.1.103 ----------> | (1)                   |
                              |                       |
 Netbook 192.168.1.113 -----> | (2)                   |
                              |                       |
                              | (3)                   |
                              |                       |
                              | (4)                   |
                              +-----------------------+

Is this what your setup looks like? What did it look like when you made a direct connection, and what did it look like when you switched back to going through the router again, while leaving the connection open?

• You don't use ssh to copy files, you use its cousin sftp, which is part of the openssh package (at least in Debian). Have a look at the manpage. If you have a connection where you're able to use ssh (whatever the wiring looks like), you type sftp 192.168.1.103. You get a prompt, in which you among other things can type "help". I'm not on a linux machine now, so the following is from memory: it accepts "dir" and "ls" (which are more or less synonymous) to show you the files of the remote machine. To copy a file from the local to the remote machine you use "put". There's also an "mput" to put multiple files using wildcards in the filename, and a command "prompt", which toggles whether you'll be prompted or not between each file in an "mput". To copy the other way, you use "get" and "mget". You can move between directories, I'm not sure if the command is "cd" or "chdir". You can delete and rename files. If you want to change the working directory on the local machine, the command is "lcd". To see the directory on the local machine: "lls" or "!ls". Preceding something with an exclamation mark, means that it will be executed on the local machine, and typing an exclamation mark only, lets you escape to a local shell, from which you can return to sftp by typing ctrl-D or "exit". And finally there are the commands "ascii" and "binary". If you are transferring between two linux machines, you should use "binary" (I think that's the default, but I'm not sure). If you are in ascii mode, you'll get a carriage return character inserted before every linefeed character, something which would ruin a binary file. The striked-out commands are not used by linux sftp, but by windows ftp. --NorwegianBlue ^talk 15:47, 4 December 2008 (UTC)

I'm on the linux box now, so I've made a couple of corrections above. --NorwegianBlue ^talk 19:59, 4 December 2008 (UTC)

Re your question: In the ssh man file I read something about X11 forwarding, which I don't follow. Can I access the remote computer with a gui using this? The answer is "yes", but you won't be able to drag-and-drop files or anything unless you mount a directory tree of one of the computers in the file system of the other. What happens is that you start a shell, which is able to spawn new gui processes that run on the remote computer, but use the screen of the local computer. When I first met unix (in 1990), remote X was real easy. However, this was in the good old days, when there were only good guys on the internet. So they had to make it more secure, and I don't think you'll want to spend the time it will take to learn how to make a modern implementation work. I addressed exactly this question in a previous post. If file transfer is what you want, I think you'll be happy using sftp. Once you solve the technical issue that's blocking the connection, it'll be real easy. --NorwegianBlue ^talk 19:59, 4 December 2008 (UTC)

See at the very top, the second line, starting with 'first the basics'. Indeed, I have a setup as you drew it (except with Netbook in 4, but that immaterial, I suppose). Then I took the netbook plug out of the router and plugged it into the pc. For which I had to unplug that too, because it only has one ethernet connection. In that setup the ssh connection worked. And then I put it back the way it was and it still worked to my surprise. It's a workaround, but provided I don't have to do this too much it will serve the purpose. However, more good news:

I got NFS to work as well! This means I can work with a gui, which is much more convenient. Just in case you wish to do this one day, and of course for other readers, here's how I got it to work:

On the server (the pc), go to yast > network services > NFS server. Firewall open on all interfaces, accept the defaults. In the next window select the partition (or whatever part of the filesystem) you want to mount. Then when you get shown the options, change 'ro' to 'rw' if you also want to be able to write to the partition. Now, on the client maybe first make a dir under which you wish to mount, then go to yast > network services > NFS client. Click 'add' and enter respectively the ip address (or name, if that works) of the server, the partition you just selected on the server, the dir under which you wish to mount that and leave the 'defaults' options as they are. Possibly do the same for more partitions (which you must then also have set up first on the server) and click 'ok'.

Some mistakes I made: I wanted to mount (on the client) partition 7 on hd S500. On the server, I have that mounted on /z/S500_7. So the thing to do was select that and any other partitions I wish to remotely mount. On the client, make a /z/ dir somewhere (as a normal user, to avoid access restrictions) (not sure if this is strictly necessaary), then open the NFS client setup and there do the chore for every single partition. But I have 11 partitions, so I tried to mount /z/ and get it over with in one go. Which doesn't work because it is not a 'physical' partition. Am I saying that correctly? Another mistake I made was to edit a file remotely, open it on the server to check if it had worked, jump around the room in excitement because it had, forget to close the file on the server, do some more experimental stuff, try editing again and notice it opens read-only. Bummer. Until I realised I had left the file open on the server. Makes sense that I can't edit it then, of course. I also wonder if mounting the same partition (or part of it) on different locations on the client is a problem. That should work, I suppose, but can also be an invitation for complications.

In short: I am satisfied now. I can copy files from the pc to the netbook. Thanks a lot for your help! DirkvdM (talk) 19:19, 4 December 2008 (UTC)

Well done! It's been a pleasure, and I'm glad you persisted. --NorwegianBlue ^talk 20:38, 4 December 2008 (UTC)

Cellphones in the United States

Hi, I'm going to stay in the US for some time, and am looking to have a local cellphone number, and, in the longer run, buy a new mobile phone. However, I'm not used to the American cellphone/calling market structure. I would appreciate if anyone could help me with answers to some of the following:

1. Can I go into a shop and buy a prepaid SIM card that I can just put in my phone and call instantly? Will I pay a high markup over the minute / SMS fees to get this? (my phone is not locked to anyone and is GSM1900 compatible)
2. Do "minutes" on the operators' web sites refer both to calls placed by me and calls received? What should I assume about SMS if nothing is said about that?
3. Is it economically feasible to buy a cellphone without at the same time signing up with a new operator (and promising to stay with them for some time)?
4. In particular, can I get an iPhone and use it without paying for an expensive AT&T subscription?
5. Is there any website comparing the prices and entry costs for various operators?

Thank you! Jørgen (talk) 19:00, 29 November 2008 (UTC)

2. Usually they mean all minutes, called and received. The best thing to assume about cell phone terms is the best possible definition for the company. Cell phone companies are rather rapacious out here.

4. Not officially. Unofficially you can "unlock" it. (see IPhone#SIM_Lock_removal).

Only ones I know the answer to, sorry! The American system is slanted very heavily towards year-long contracts, as you probably know. If you will be here for around a year, it's best to just do one of those. For less amount of times, there will probably be a trade-off between prepaid and contract service. Specifics no doubt vary from carrier to carrier. US cellphone system sucks. :-( --98.217.8.46 (talk) 19:34, 29 November 2008 (UTC)

Look at the amount of time you'll be using it, or at least try to guesstimate it; if it's very little, a tracfone (sp?) might be advantageous, as you pay a very small fee compared to a yearly contract plus phone bill. You simply buy extra minutes when you need, I think. You might be out the contract amount if you don't stay a year, but you won't have used as many minutes.209.244.30.221 (talk) 19:39, 29 November 2008 (UTC)

With a Tracfone, you don't have any subscription. You buy the phone and then go to a store like Walmart and buy a phone card (check to make sure it's the right one, though!). Then I'm not sure of the process, but you have to put in the pin number on the card and it will unlock the minutes on your phone. Very easy and very good if you aren't going to use as many minutes as on a normal plan or won't be there as long as a contract would want you to be. EDIT: also, it's cheaper because you ONLY buy minutes you need. 24.180.87.119 (talk) 23:31, 29 November 2008 (UTC)

Since we're talking about brand names here, I'll throw my 2¢ in about T-Mobile pre-paid. I believe it's the cheapest of the pre-paid. There's no daily "Access Fee" if you use the phone or not. Normally the service is 25¢ a minute and they expire in 90 days. But if you buy more than $100 in minutes at once, the prices plummets to 10¢/min and they expire in a year. I don't think any other pre-paid service can beat 10¢ a minute. Technically any phone can be made pre-paid by a T-Mobile service center -- they just need to program the SIM to recognize the pre-pay codes. But you can buy pre-packaged pre-paid T-Mobile phones in any Target or Wal-Mart (I think there are four models to choose from). Not sure what the pricing structure is for data and smartphones like Blackberry. --70.130.54.91 (talk) 06:05, 30 November 2008 (UTC)

Thank you all! Of course, if anyone wants to add more, I'd be grateful. Where I live now the notion of having to "use up your minutes", ie paying for anything else than what you actually call, is quite unheard of, however the operators have started to try to push it... Jørgen (talk) 18:34, 30 November 2008 (UTC)

Back button not there first time I open a page, is there after

Not always, but often on AOL, I will open a page, do some clicking on links, and be unable to get back becasue the browser's back button isn't cluckable. However, if I open the same page and do the same thing, it is there.

It's not limited to AOL searches, either; on Wikipedia, that set of 4 tildes to indicate signing my query can't be clicked on to automatically link to it and thus insert my signature; it has to be copied and pasted. And yet, if I go back to it a 2nd time, it is.

Is this some weird, freaky virus? It's really only an annoyance so I'm nto to concerned, but still, it would be nice to know what's going on. Thanks.209.244.30.221 (talk) 19:03, 29 November 2008 (UTC)

Sounds less like a freaky virus than it does a bad browser, one that is getting awfully confused or not implementing javascript correctly (in the case of the signature button). --98.217.8.46 (talk) 19:28, 29 November 2008 (UTC)

What browser do you use? (Note: I am so tempted to make a chicken joke, but shall refrain...) 24.180.87.119 (talk) 23:34, 29 November 2008 (UTC)

If you won't, I will, even if I risk running a fowl of the OP: "What kind of chicken-shit browser has a back button that isn't always cluckable ? Those programmers at AOL must all have egg on their faces.". StuRat (talk) 03:21, 30 November 2008 (UTC)

AOL has their own browser, which is basically just Internet Explorer with some additional bugs added in. StuRat (talk) 03:23, 30 November 2008 (UTC)

Beware that some links open in a new window, which lacks a back button since there is no previous page in that window. In such cases, you must close, move, or minimize the new window to see the previous page on the old window. StuRat (talk) 03:21, 30 November 2008 (UTC)

Could I draw the OP's attention to a free and open source web browser that is Mozilla Firefox? Kushal (talk) 14:21, 30 November 2008 (UTC)

What is the easiest way to save Hotmail emails to hard disk?

Please? 78.144.244.16 (talk) 23:24, 29 November 2008 (UTC)

I'd just copy and paste it into a text file (using Wordpad or even Notepad) and then save it normally. I don't know of any way you could possibly do it more easily. 24.180.87.119 (talk) 23:28, 29 November 2008 (UTC)

Manually, for all 5000000 of them? Sorry, I should have said I want to back up all of them, too many to do individually. Thanks. 78.144.244.16 (talk) 00:21, 30 November 2008 (UTC)

How about forwarding a whole load of them to another account? Turns 50 mails into one mail. Astronaut (talk) 00:27, 30 November 2008 (UTC)

Checking out my Hotmail, seems you can't attach a mail to another. Sorry. Astronaut (talk) 00:35, 30 November 2008 (UTC)

According to Hotmail#Desktop mail client access, Windows Live Mail has the ability to access Hotmail, and it presumably should have some way of saving emails; also if you have Microsoft Outlook, you can install the Microsoft Office Outlook Connector and use your Hotmail with Outlook. If you pay for a Hotmail Plus account, you can access it with any POP3 program, and then it would be easy to save stuff. --128.97.245.72 (talk) 00:31, 30 November 2008 (UTC)

Help with .emp file format.

OK, so I downloaded some music from eMusic.com and it's in this weird .emp format. How can I play it or change it to, like, mp3 format? Thanks. —Preceding unsigned comment added by 24.180.87.119 (talk) 23:25, 29 November 2008 (UTC)

It looks like .emp is a playlist of the music, not the music itself. You should install the official eMusic download manager or an unofficial alternative (like [2]). F (talk) 08:35, 1 December 2008 (UTC)

OK, thanks... I have the download manager now, but the three files in .emp format I have won't show up. I got some free downloads, so I don't really want to waste them redownloading the music. I guess I can try to mess around with it more and see if I can get it to work. 24.180.87.119 (talk) 05:31, 2 December 2008 (UTC)