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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" }

Enable cd by variable names
Usage: $ mydir=/very/long/path/to/a/dir $ cd mydir I often need to cd where no man wants to go (i.e. long path). by enabling the shell option cdable_vars, I can tell cd to assume the destination is the name of a variable.

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

Ping all hosts on 192.168.1.0/24
Pings all the hosts on 192.168.1.0/24 in parallel, so it is very fast. Alive host IP addresses are echoed to stdout as pings are responded to.

Enable color pattern match highlighting in grep(1)
This will affect all invocations of grep, even when it is called from inside a script.

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"

count total number of lines of ruby code
Adapted from http://stackoverflow.com/questions/1358540/how-to-count-all-the-lines-of-code-in-a-directory-recursively#answer-1359246

Easily decode unix-time (funtion)

Ask user to confirm
This version works across on all POSIX compliant shell variants.

Backup with versioning
Apart from an exact copy of your recent contents, also keep all earlier versions of files and folders that were modified or deleted. Inspired by EVACopy http://evacopy.sourceforge.net


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