Differing Features (UNIX in a Nutshell: System V Edition)

3.5. Differing Features

The following table displays features that are different among the three shells.

sh	ksh	csh	Meaning/Action
`$`	`$`	`%`	Prompt.
	`>\|`	`>!`	Force redirection.
		`>>!`	Force append.
`>` `file` `2>&1`	`>` file `2>&1`	`>&` file	Combine stdout and stderr.
		`{ }`	Expand elements in list.
`‘ ‘`	`‘ ‘`	`‘ ‘`	Substitute output of enclosed command.
	`$( )`		Substitute output of enclosed command. (Preferred form.)
`$HOME`	`$HOME`	`$home`	Home directory.
	`~`	`~`	Home directory symbol.
`var``=value`	var`=`value	`set` var=value	Variable assignment.
`export` `var`	`export` var`=`val	`setenv` var val	Set environment variable.
	`${``nn``}`		More than nine args can be referenced.
`"$@"`	`"$@"`		All args as separate words.
`$#`	`$#`	`$#argv`	Number of arguments.
`$?`	`$?`	`$status`	Exit status.
`$!`	`$!`		Background exit status.
`$-`	`$-`		Current options.
`.` `file`	`.` file	`source` file	Read commands in file.
	`alias` `x``=y`	`alias` x y	Name x stands for y.
`case`	`case`	`switch/case`	Choose alternatives.
	`cd ~-`	`popd/pushd`	Switch directories.
`done`	`done`	`end`	End a loop statement.
`esac`	`esac`	`endsw`	End `case` or `switch`.
`exit [``n``]`	`exit [`n`]`	`exit [(`expr`)]`	Exit with a status.
`for/do`	`for/do`	`foreach`	Loop through variables.
	`print -r`	`glob`	Ignore `echo` escapes.
`hash`	`alias -t`	`hashstat`	Display hashed commands (tracked aliases).
`hash` `cmds`	`alias -t` cmds	`rehash`	Remember command locations.
`hash -r`	`PATH=$PATH`	`unhash`	Forget command locations.
	`history`	`history`	List previous commands.
	`r`	`!!`	Redo previous command.
	`r` `str`	`!`str	Redo command that starts with str.
	`r` `x``=cmd`	`!`cmd`:s/`x/y	Edit command, then execute.
`if [ $i -eq 5 ]`	`if ((i==5))`	`if ($i==5)`	Sample `if` statement.
`fi`	`fi`	`endif`	End `if` statement.
`ulimit`	`ulimit`	`limit`	Set resource limits.
`pwd`	`pwd`	`dirs`	Print working directory.
`read`	`read`	`$<`	Read from standard input.
`trap 2`	`trap 2`	`onintr`	Ignore interrupts.
	`unalias`	`unalias`	Remove aliases.
`until/do`	`until/do`		Begin `until` loop.
`while/do`	`while/do`	`while`	Begin `while` loop.