d

dec2hex

    read from files or stdin if no file is specified, in which
    each line should be a decimal number. Output the number in
    hexadecimal format.

f

forever: run a command and never stop even when it fails

foreverif: run a command until it fails

h

hexdump

    dump the content of the file in hex mode

hex2dec

    reverse the functionality of dec2hex.

k

kill-command

    kill command with keywords.

m

memwatch

    watch a child process's memory usage

o

once: run a command once and print the exit code

r

random:

        generate random numbers using options --limit --min --max --sum

replace:

        apply sed to replace <old> to <new> in files.

set

Useful when setting up environment

set_exit

print out the exit code when it does not finish successfully (0).