Regular Expression

Symbol/Command

Meaning/Action

>  >>  <  <<  | & ; * ? !n [] () “” ‘’ \ $var $$ $0 $n $* $? # Tab bg break cd continue echo eval exec fg jobs kill newgrp shift stop suspend umask unset wait

Redirect output Append output to file Redirect input “Here” document (redirect input) Pipe output Run process in background Separate commands on same line Match any character(s) in filename Match single character in filename Repeat command number n. Match any characters enclosed. Execute in subshell Partial quote (allows variable and command expansion). Preserve literal value of enclosed characters Quote following character. Use value for variable. Process ID. Command name. nth argument (0<n≤9) All arguments. Exit status. Begin comment Complete current word. Background execution Break from loop statements. Change directories. Resume a program loop. Display output. Evaluate arguments. Execute a new shell or other program. Foreground execution. Show active jobs. Terminate running jobs. Change to a new group Shift positional parameters. Suspend a background job. Suspend a foreground job. Set or list permissions on files to be created. Erase variable or function definitions. Wait for a background job to finish.