man whatis … -h / ./ ../ ~/ * ? […] \  "…" '…' ls ls -l ls -a tree stat pwd cd pushd popd dirs mkdir rmdir cp cp -a ln ln -s mv rm rm -r rm -f ssh user@host scp … user@host:file … sftp whoami groups id passwd w -n who last write mesg wall su r w x suid sgid r w x sticky umask chmod numerycznie symbolicznie chgrp chown touch 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… Ctrl+Z … & jobs fg bg wait nice renice taskset ionice numactl cat paste join fold column -t od hexdump xxd echo printf seq > >> 2> &> < << EOF <<< /dev/null