Difference Between Sh, Ksh, Csh And Bash

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Always wondered what is the difference between these four shells? Here’s the answer.

 

As a command line beginner or new Linux/Unix user, you must have come across these common shell names, Standard shell (sh), Bourne Again SHell (bash), Korn shell (ksh) and the C shell (csh). And if you are among those wondering what makes them stand apart from each other, here’s a comparative chart for you to see.Please note how bash incorporates almost every concept from other shells, as there are no blanks in the column for bash. Moreover, this is just a comparative list that lays out the major differences between the standard shell (sh), Bourne Again SHell (bash), Korn shell (ksh) and the C shell (csh).
Meaning/Action sh ksh csh bash
Default user prompt $ $ % $
Force redirection   >| >! >|
Redirect stdout and stderr to file > file 2>&1 > file 2>&1 >& file &> file or > file 2>&1
Expand elements in list     { } { }
Substitute output of enclosed command `command` $(command) `command` `command` or $(command)
Home directory $HOME $HOME $home $HOME
Home directory symbol   ~ ~ ~
Access directory stack   ~+, ~- Err:511 ~+, ~-, dirs
Variable assignment var=value var=value set var=value VAR=value
Set environment variable export var export var=val setenv var val export VAR=value
More than 9 arguments can be referenced   ${nn}   ${nnnn}
All arguments as separate words “$@” “$@”   “$@”
Number of arguments $# $# $#argv $#
Exit status of the most recently executed command $? $? $status $?
PID of most recently backgrounded process $! $!   $!
Current options $- $-   $-
Read commands in file . file . file source file source file or . file
Name x stands for command y   alias x=y alias x y alias x=’y’
Choose alternatives case case switch or case case
End a loop statement done done end done
End case or switch esac esac endsw esac
Exit with a status exit n exit n exit (expr) exit n
Loop through variables for/do for/do foreach for/do
Ignore substitution characters for filename generation     noglob set -f , set -o nullglob|dotglob|nocaseglob|noglob
Display hashed commands (tracked aliases) hash alias -t hashstat hash
Remember command locations hash cmds alias -t cmds rehash hash cmds
Forget command locations hash -r   unhash hash -r
List previous commands   history history history
Redo previous command   r !! ArrowUp+Enter or !!
Redo last command that starts with “str”   r str !str !str
Replace “x” with “y” in most recent command starting with “cmd”, then execute.   r x=y cmd !cmd:s/x/y/ !cmd:s/x/y/
Sample condition test if [ $i -eq 5 ] if ((i==5)) if ($i==5) if [ $i -eq 5 ]
End if statement fi fi endif fi
Set resource limits ulimit ulimit limit ulimit
Print working directory pwd pwd dirs pwd
Read from terminal read read $< read
Ignore interrupts trap 2 trap 2 onintr trap 2
Remove aliases   unalias unalias unalias
Begin until loop until until   until
Begin while loop while/do while/do while while/do

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