6. Frequently-asked questions

  • How do I copy files from another machine? You can use the scp program to push or pull files to and from machines. For instance, to copy a file myfile.txt from a machine called rabbit.physics.ox.ac.uk, log into linux.ox.ac.uk and type 
     scp rabbit.physics.ox.ac.uk:myfile.txt myfile.txt
    You will be asked for your password, and then myfile.txt will be placed in your current directory. You can copy an entire directory and all its contents (including subdirectories) with appropriate options to scp. Thus to copy all of the directory Workfiles from rabbit, type 
                    scp -p -r rabbit.physics.ox.ac.uk:Workfiles Workfiles
    (the -p options tells scp to preserve the datestamp on files).
Is this Unix?
Informally, yes. Legally, no. This service is running Debian GNU/Linux, an open-source and free alternative to Unix. In practice, all the standard Unix commands and facilities behave identically under Linux.
Is there some temporary space for big files?
Yes, you can create files in $TMPDIR, but they are not guarenteed to still exist after you log out. This facility is for files you need during your current session, not for temporary storage over several days. Files will also be deleted when they get to be a week old, so their life time is per-session or 7 days, whichever is shortest. In summary, if you logout and login again, you cannot rely on the contents of the temporary directory still being there. Note also that the temporary directory depends on which node you log into; if you log in twice, you may not be on the same machine for both sessions.
What shells are available?
The default login shell is bash, the Bourne Again Shell. If you prefer to use C Shell, tcsh is available. To invoke this for a single session, type 
exec tcsh
To set this as your default shell for future logins, use the web-based account management interface.
FTP doesn't seem to work - what can I do ?
FTP has two modes - active and passive. Due to the firewall in front of the linux server, active FTP doesn't work. Thus to use FTP you have to use passive mode, to do this run ftp -p or pftp
Can I print to a remote printer?
You can send print jobs to a remote lpd server (line printer daemon) using the rlpr command. See the rlpr manual page for full details and examples. Please contact your local IT support staff for information about printers and print servers in your college or department.

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