man whatis apropos … -h root dir home dir / ./ ../ ~/ * ? […] \  "…" '…' ls ls -l ls -a tree stat pwd cd pushd popd dirs history pick your favourite… mkdir rmdir cp cp -a ln ln -s mv rm rm -r rm -f ssh user@host scp … user@host:file … sftp time sleep timeout pid ppid parent child zombie ps ps -e ps -l ps -f pstree /proc/… top htop kill kill -SIG… INT TERM KILL STOP CONT pgrep pkill -f pidof killall -SIG… nice renice taskset ionice numactl whoami groups id passwd w -n who last write mesg wall su r w x suid sgid r w x sticky umask chmod octal numbers symbolic chgrp chown touch cat paste join fold column -t od hexdump xxd echo printf seq > >> 2> &> < << EOF <<< /dev/null   |   mkfifo head tail tail -f grep cut -s … -f … cut -b … sort wc uniq nl tac rev tr sed awk more less tee locate find by name/path by owner/perms by size by dates shebang perms .  ; & && || { … ; } (…) Ctrl+Z … & jobs fg bg wait X=5 $X ${X} export X $1, $2, … $# "$@" "$*" $* $@ $0 $$ $! $? $PATH $RANDOM env set unset $((…)) $(…) `…` alias read test … [ … ] text numbers files if … then … elif … else … fi case … in …) … ;; esac for … in … while … until … do … done break continue myName(){ … ; } return exit trap "…" SIG… trap "…" EXIT .bashrc