This command sequence allows simple setup of (gasp!) password-less SSH logins. Be careful, as if you already have an SSH keypair in your ~/.ssh directory on the local machine, there is a possibility ssh-keygen may overwrite them. ssh-copy-id copies the public key to the remote host and appends it to the remote account's ~/.ssh/authorized_keys file. When trying ssh, if you used no passphrase for your key, the remote shell appears soon after invoking ssh user@host.

This invokes tar on the remote machine and pipes the resulting tarfile over the network using ssh and is saved on the local machine. This is useful for making a one-off backup of a directory tree with zero storage overhead on the source. Variations on this include using compression on the source by using 'tar cfvp' or compression at the destination via ssh user@host "cd dir; tar cfp - *" | gzip - > file.tar.gz

Thanks to OpenSSL, you can quickly and easily generate MD5 hashes for your passwords. Alternative (thanks to linuxrawkstar and atoponce): echo -n 'text to be encrypted' | md5sum - Note that the above method does not utlise OpenSSL. Show Sample Output

A simple but effective replacement for ps aux. I used to waste my time running ps over and over; top is the way to go. It also allows complex sorting options. Press q to exit "nicely" (Ctrl + C is always an option, of course). Note that the list updates each second, resorting in the process; if you're trying to grab a specific PID, you might be better off with ps. htop Alternatively, htop is available, though it may not come pre-installed. htop is slightly more interactive than top and includes color coding, visuals, and a nice interface for selecting and then killing processes. (Thanks to bwoodacre for this great tool.) Show Sample Output

You're running a script, command, whatever.. You don't expect it to take long, now 5pm has rolled around and you're ready to go home... Wait, it's still running... You forgot to nohup it before running it... Suspend it, send it to the background, then disown it... The ouput wont go anywhere, but at least the command will still run... Show Sample Output

Ever had a file with a list of numbers you wanted to add, use: cat file | sed ':a;N;$!ba;s/\n/+/g' | bc

This will send a test print job to a networked printer.

This command shows if there are any locked AFS volumes. The output is a list of AFS volume IDs (or nothing if there are none locked). Show Sample Output

Show the webcam output with mplayer.

Change bash autocomplete case search to insensitive when pressing tab for completion.

Substitute spaces in filename with underscore, it work on the first space encountered.

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Find out which RPMs were installed on a particular date. These would (naturally) include update RPMs. This example shows searching for "Thu 05 Mar" (with grep). Alternatively, pipe it to less so you can search inside less (with less's neat text highlighting of the search term): rpm -qa --queryformat '%{installtime} \"%{vendor}\" %{name}-%{version}-%{release} %{installtime:date}\n' | less # (this example) search term: Thu 05 Mar Show Sample Output

"play" is part of "SoX" SoX - Sound eXchange, the Swiss Army knife of audio manipulation. For details, see: man sox Show Sample Output

Create backup (.tar.gz) for all first-level directory from current dir. Show Sample Output

This command will tell lynx to read keystrokes from the specified file - which can be used in a cronjob to auto-login on websites that give you points for logging in once a day *cough cough* (which is why I used -accept_all_cookies). For creating your keystroke file, use: lynx -cmd_log yourfile

At the start of a vi session and *before* saving any changes use ":!cp % %-" to make a backup of the current file being edited. example: vi /data/some/long/path/file :!cp% %- creates /data/some/long/path/file-

Using the "#" in shell is surprisingly useful. Some of the uses I found: a) As a visible copy buffer in shell history (caveat: do not use for passwords :-) b) To build complex commands until ready then hit the HOME, DEL, ENTER keys to run it c) Placing reference data into shell history (search for tags with CTRL-R TAGNAME) d) Putting aside a "work in progress" command to focus on another task (HOME # ENTER) Show Sample Output

Hold ctrl and press z to pause the current thread. Run fg to resume it.

Add calendar to desktop wallpaper , mess with the coordinates to place where you like