awk apache http server bcpl basename bc programming language bourne shell buffer overflow c standard library chgrp chmod chown chroot cksum comm common lisp cron curly bracket programming language data type decimal env escape character escape sequence exception handling expr find finger protocol format string attack freebsd fsck function prototype glib gnu compiler collection gnu octave grep hexadecimal iconv inetd iostream itoa javascript killall korn shell libiberty list of unix utilities logname ls lsattr lsof matlab maple mathematica mesg mkdir multics mv netbsd netcat netstat objective caml openbsd php posix perl pgrep pidof ping pkill placeholder pstree pwd rlogin rmdir scanf sed shell script string literal subroutine sudo syntax the open group tput traceroute umask uname uniq unix unset uptime variadic function xargs z shell zetalisp