Commands by twjolson (5)

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from the console, start a second X server
This starts a very basic X session, with just a simple xterm. You can use this xterm to launch your preferred distant session. $ ssh -X john@otherbox gnome-session Try also startkde or fluxbox or xfce4-session. To switch between your two X servers, use CTRL+ALT+F7 and CTRL+ALT+F8.

delete PBS jobs based on strings from qstat output

Perform a branching conditional
This will perform one of two blocks of code, depending on the condition of the first. Essentially is a bash terniary operator. To tell if a machine is up: $ ping -c1 machine { echo succes;} || { echo failed; } Because of the bash { } block operators, you can have multiple commands $ ping -c1 machine && { echo success;log-timestamp.sh }|| { echo failed; email-admin.sh; } Tips: Remember, the { } operators are treated by bash as a reserved word: as such, they need a space on either side. If you have a command that can fail at the end of the true block, consider ending said block with 'false' to prevent accidental execution

remove empty lines

Convert CSV to JSON
Replace 'csv_file.csv' with your filename.

for newbies, how to get one line info about all /bin programs
Get simple description on each file from /bin dir, in list form, usefull for newbies.

convert single digit to double digits
works only in zsh, requires autoload zmv

Replace duplicate files by hardlinks

Show a script or config file without comments or blank lines

Check a server is up. If it isn't mail me.
This version uses netcat to check a particular service.


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