| Bourne Shell | C Shell
differences |
MsDos
batch |
Comment |
| sh | csh | file.bat | command |
| 1978 | 1978 | year introduced | |
| #!/bin/sh | #!/bin/csh | Unix first line | |
| # | REM comment but parses line
:: comment |
Comment | |
| set -v | set verbose | verbose on | |
| set +v | unset verbose | verbose off | |
| set -x | set echo | @echo on | debug mode on |
| set +x | unset echo | @echo off | debug mode off |
| $1, $2, ..., $9 | %1, %2, ..., %9 | command-line arguments | |
| shift | shift | shift | shift args one position by one |
| $# | number of command-line args | ||
| $0 | name of command | ||
| echo "$*"
echo "$1 $2 $3 ... " |
glob all args in one string | ||
| echo "$@"
echo "$1" "$2" "$3" ... |
give all args as seperate strings | ||
| $? | $status | exit status
if referenced more than once then must save in variable |
|
| V=1 | set V 1 | set V=1 | variable assignment
no blanks around equal sign |
| V=$W | set V $W | set V=%W% | |
| $V | %V% | Variable Ref | |
| echo $V
echo ${V} |
echo %V% | display | |
| V='abc$Wdef' | set V='abc$Wdef' | literal string
='single quotes' =no $variable substitution =no ${varible} substitution =useful for blanks/spaces |
|
| V="abc$Wdef" #error
V="abc${W}def" #correct |
non-literal string
="double quotes" =$variables substitution =useful for blanks/spaces |
||
| V=`expr $N + 1` | executable string
=`grave accent quotes' =useful for arithmetic =stdout assigned to variable |
||
| unset V | unsetenv V | clear variable | |
| ${V} | %V% | Variable Ref | |
| cmd1 ; cmd2 | sequental commands | ||
| cmd1 && cmd2 | logical AND | ||
| cmd1 || cmd2 | logical OR | ||
| cmd1 | cmd2
cmd1>f1; f1 < cmd2 |
pipe | ||
| ( subshell-cmd ) | creates a subshell to run
commands as a separate process |
||
| (cd /tmp;ls);ls | example | ||
| { cmds } | within same shell
brace must be followed by blank |
||
| { date; who }>file.txt | example | ||
| echo 'msg=$V' | literal string =
single quotes = no $variable substitution |
||
| program
if [ $? -eq 0 ]; then echo "program ok"; fi |
if ERRORLEVEL 0 echo "program ok" | testing exit status of
last program excuted |
|
| program
if [ $? -ne 0 ]; then echo "error"; fi; |
if NOT ERRORLEVEL 0 echo "error" | testing exit status of
last program executed |
|
| if [ -n $V ]; then echo "not empty"; fi
if test -n $V; then echo "not empty"; fi test -n $V; if [ $? -eq 0 ]; then echo "not empty"; fi |
if NOT %V%=="" echo "not empty" | string comparison: non-zero | |
| if [ -z $V ]; then echo "empty"; fi
if test -z $V; then echo "empty"; fi test -z $V; if [ $? -eq 0 ]; then echo "empty"; fi |
if %V%=="" echo "empty" | string comparison: zero | |
| if [ -f $V ]; then echo "file exists"; fi
if test -f $V; then echo "file exists"; fi |
if exist %V% echo "file exists" | file comparison | |
| if [ -d $V ]; then echo "directory exists"; fi
if test -d $V; then echo "directory exists"; fi |
file comparison | ||
| if [ -d $V ] || [ -f $W ]; then echo "dir or file"; fi | |||
| if [ $S = $T ]; then echo "string equal"; fi
if test $S = $T ; then echo "string equal"; fi |
if %S% == %T% echo "string equal" | string comparison | |
| if [ $S != $T ]; then echo "not equal"; fi
if test $S != $T ; then echo "not equal"; fi if [ ! $S = $T ]; then echo "not equal"; fi if test ! $S = $T ; then echo "not equal"; fi |
if NOT %S% == %T% echo "not equal" | string comparison | |
| if [ $I -eq $N ]; then echo "integers equal"; fi | integer comparison | ||
| if [ $I -ne $N ]; then echo "integers not equal"; fi | integer comparison | ||
| if [ $I -lt $N ]; then echo "integer less than"; fi | integer comparison | ||
| if [ $I -le $N ]; then echo "integer less than or equal"; fi | integer comparison | ||
| if [ $I -gt $N ]; then echo "integer greater than"; fi | integer comparison | ||
| if [ $I -ge $N ]; then echo "integer greater than or equal"; fi | integer comparison | ||
| if commands; then commands; else commands; fi | |||
| for V in 1 2 3 4; do echo $V; done | for %%V in ( 1 2 3 4 ) do echo %V | ||
| N="1 2 3 4"; for V in $N; do echo $V; done | set V="1 2 3 4"
for %%V in ( %N ) do echo %V |
||
| N=1; while [ $N -le 4 ]; do echo $N; N=`expr $N + 1`; done | |||
| f(){ echo $1; } #define a function f
f abc #call function f with arg abc |
function | ||
| date > out; ls >> out; date >> out
( date ; ls ; date ) > out |
common output |