Quick Unix shell cross reference guide for portability needs

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

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