Common Features (Linux in a Nutshell, 3rd Edition)

6.3. Common Features

The following table is a sampling of features that are common to bash, csh, and tcsh. Note that tcsh is an enhanced version of csh; therefore, tcsh includes all features of csh, plus some others.

Symbol/Command	Meaning/Action
`>`	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.
`!`n	Repeat command number n.
`[ ]`	Match any characters enclosed.
`( )`	Execute in subshell.
` `	Substitute output of enclosed command.
`" "`	Partial quote (allows variable and command expansion).
`\`	Quote following character.
`$`var	Use value for variable.
`$$`	Process ID.
`$0`	Command name.
`$`n	nth argument (0<n9).
`$*`	All arguments.
`#`	Begin comment.
`bg`	Background execution.
`break`	Break from loop statements.
`cd`	Change directories.
`continue`	Resume a program loop.
`echo`	Display output.
`eval`	Evaluate arguments.
`exec`	Execute a new shell or other program.
`fg`	Foreground execution.
`jobs`	Show active jobs.
`kill`	Terminate running jobs.
`newgrp`	Change to a new group.
`shift`	Shift positional parameters.
`stop`	Suspend a background job.
`suspend`	Suspend a foreground job.
`umask`	Set or list permissions on files to be created.
`unset`	Erase variable or function definitions.
`wait`	Wait for a background job to finish.