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Convert seconds to [DD:][HH:]MM:SS
Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

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"

run complex remote shell cmds over ssh, without escaping quotes
Much simpler method. More portable version: ssh host -l user "`cat cmd.txt`"

Determine whether a CPU has 64 bit capability or not

Remove security limitations from PDF documents using ghostscript (for Windows)
#4345 also works under windows

Delete all empty lines from a file with vim
If you need to delete lines that may contain space characters (such as tabs or spaces) as well as empty ones, try: $:v/\S/d Just an alternative.

dump the whole database

Ask for a password, the passwd-style
You can ask repeatedly for a non-blank password using this function: function read_password() { while [ ! -n "$USER_PASSWORD" ]; do read -s -p"Password: " USER_PASSWORD if [ ! -n "$USER_PASSWORD" ]; then echo "ERROR: You must specify a valid password, please try again" fi echo done } Also you can set a time out (in seconds) to write the password read -t 10 -s -p"Password: " USER_PASSWORD_VARIABLE if [ ! $? -eq 0 ]; then echo "Time out!" fi

Simple way to envoke a secure vnc session through ssh enabled router.
The ip address is of the remote machine running the vncserver. Must log in first to the router then the VNC session. Very nice if you have open-wrt or dd-wrt on your router.

List complete size of directories (do not consider hidden directories)
why make it complicated ? : ] -------------------- I just noticed someone else has posted this on this site before me (sorry I am now a duplicate :/) http://www.commandlinefu.com/commands/view/4313


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