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Show max lengths of all fields in a pipe delimited file with header row

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"

Propagate X session cookies on a different user and login as that user
Reads a username from

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" }

Show bandwidth use oneliner
poorman's ifstat using just sh and awk. You must change "eth0" with your interface's name.

extract column from csv file
extracts the 5th column using the delimiter ','

Paste the contents of OS X clipboard into a new text file

Create md5sum of files under the current dir excluding some directories
Useful if you want get all the md5sum of files but you want exclude some directories. If your list of files is short you can make in one command as follow: $ find . -type d \( -name DIR1 -o -name DIR2 \) -prune -o -type f -exec md5sum {} \; Alternatively you can specify a different command to be executed on the resulting files.

List your MACs address
The output of ifconfig is localized, using it will fail in non-English environment. "ip" command in iproute2 provides a consistent output and thus is more robust

Eavesdrop on your system
This command takes a snapshot of the open files for a PID 1234 then waits 10 seconds and takes another snapshot of the same PID, it then displays the difference between each snapshot to give you an insight into what the application is doing.


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