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Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

check open ports without netstat or lsof

Check a nfs mountpoint and force a remount if it does not reply after a given timeout.
Based on the execute with timeout command in this site. A more complex script: #!/bin/sh # This script will check the avaliability of a list of NFS mount point, # forcing a remount of those that do not respond in 5 seconds. # # It basically does this: # NFSPATH=/mountpoint TIMEOUT=5; perl -e "alarm $TIMEOUT; exec @ARGV" "test -d $NFSPATH" || (umount -fl $NFSPATH; mount $NFSPATH) # TIMEOUT=5 SCRIPT_NAME=$(basename $0) for i in $@; do echo "Checking $i..." if ! perl -e "alarm $TIMEOUT; exec @ARGV" "test -d $i" > /dev/null 2>&1; then echo "$SCRIPT_NAME: $i is failing with retcode $?."1>&2 echo "$SCRIPT_NAME: Submmiting umount -fl $i" 1>&2 umount -fl $i; echo "$SCRIPT_NAME: Submmiting mount $i" 1>&2 mount $i; fi done

Print just line 4 from a textfile
this method should be the fastest

list block devices
Shows all block devices in a tree with descruptions of what they are.

extract element of xml
Prints the value of a XML node rather than the entire node.

Rename files in batch

Remove Backup Files
Remove all text backup files.

Check which files are opened by Firefox then sort by largest size.
Just refining last proposal for this check, showing awk power to make more complex math (instead /1024/1024, 2^20). We don't need declare variable before run lsof, because $(command) returns his output. Also, awk can perform filtering by regexp instead to call grep. I changed the 0.0000xxxx messy output, with a more readable form purging all fractional numbers and files less than 1 MB.

external projector for presentations
i spent way too many hours trying to fiddle with /etc/X11/xorg.conf trying to hook up various external projectors. too bad i didn't know this would solve all my problems.


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