Others useful commands on linux

# alias hh='history'

set an alias for a command - hh = history [man]

# apropos ...keyword

display a list of commands that pertain to keywords of a program , useful when you know what your program does, but you don't know the name of the command [man]

# chsh

change shell command [man]

# chsh --list-shells

nice command to know if you have to remote into another box [man]

# gpg -c file1

encrypt a file with GNU Privacy Guard [man]

# gpg file1.gpg

decrypt a file with GNU Privacy Guard [man]

# ldd /usr/bin/ssh

show shared libraries required by ssh program [man]

# man ping

display the on-line manual pages for example on ping command - use '-k' option to find any related commands [man]

# mkbootdisk --device /dev/fd0 `uname -r`

create a boot floppy [man]

# wget -r www.example.com

download an entire web site [man]

# wget -c www.example.com/file.iso

download a file with the ability to stop the download and resume later [man]

# echo 'wget -c www.example.com/files.iso' | at 09:00

start a download at any given time [man]

# whatis ...keyword

displays description of what a program does [man]

# who -a

show who is logged on, and print: time of last system boot, dead processes, system login processes, active processes spawned by init, current runlevel, last system clock change [man]