Shell Programming and Scripting

var='Regular expressions rules!'
$ echo ${var//e/#}
R#gular #xpr#ssions rul#s!

var='Regular expressions rules!'
$ echo ${var//!(e)/#}
#

${variable_name}

*(exp), ?(exp), !(exp) ...

grep "e*" ...

if [[ $var == *!(e)* ]]

#!/bin/bash -
#!/bin/ksh -

# @(#) s1       Demonstrate string operators.

echo "(Versions displayed with local utility \"version\")"
version >/dev/null 2>&1 && version =o $(_eat $0 $1)

var='String operators rule!'
echo
echo " Replace e with _:"
echo ${var//e/_}

echo
echo " Replace everything except e with _:"
echo ${var//[^e]/_}

exit 0

% ./s1
(Versions displayed with local utility "version")
Linux 2.6.11-x1
GNU bash 2.05b.0

 Replace e with _:
String op_rators rul_!

 Replace everything except e with _:
_________e__________e_

var='jo mike and dave are good friends'

$ echo ${var//a?(re)/_}
# returns > jo mike _nd d_ve _ good friends

$ echo ${var//g*(o)/_}
#returns > jo mike and dave are _d friends

$ echo ${var//+(o)/_}
#returns > j_ mike and dave are g_d friends

$ echo ${var//@(jo|dave)/_}
#returns > _ mike and _ are good friends

$ /usr/dt/bin/dtksh
$ set -o emacs
$
$ x=hello
$ echo ${x//l/X} ${x//[!l]/X}
heXXo XXllX
$

#!/usr/bin/ksh93

echo ${.sh.version}
var='A regular expressions test'

echo "1>  //e/#"
echo ${var//e/#}
echo "2>  //[^e]/#"
echo ${var//[^e]/#}
echo "3>  //+(e)/#"
echo ${var//+(e)/#}
echo "4>  //-(e)/#"
echo ${var//-(e)/#}
echo "5>  //?(e)/#"
echo ${var//?(e)/#}
echo "6>  //*(e)/#"
echo ${var//*(e)/#}
echo "7>  //!(e)/#"
echo ${var//!(e)/#}

Version M 1993-12-28 s+
1>  //e/#
A r#gular #xpr#ssions t#st
2>  //[^e]/#
###e######e###e########e##
3>  //+(e)/#
A r#gular #xpr#ssions t#st
4>  //-(e)/#
A regular expressions test
5>  //?(e)/#
###########################
6>  //*(e)/#
###########################
7>  //!(e)/#
#

#!/usr/dt/bin/dtksh
#!/usr/bin/ksh -
#!/usr/xpg4/bin/sh -
#!/bin/ksh -
#!/bin/bash -

# @(#) s2       Demonstrate pattern matching in dtksh and sed.

echo "(Versions displayed with local utility \"version\")"
version >/dev/null 2>&1 && version =o $(_eat $0 $1)

var='Regular expressions rules!'
echo
echo " Replace e with _:"
echo ${var//e/_}

echo
echo " Replace everything except e with _:"
echo re ${var//!(e)/_}
echo fe ${var//[!e]/_}

echo
echo " Replace everything except e with _ using sed:"
echo "$var" | sed -e 's|[^e]|_|g'

exit 0

$ ./s2
(Versions displayed with local utility "version")
SunOS 5.10
dtksh M-12/28/93d

 Replace e with _:
R_gular _xpr_ssions rul_s!

 Replace everything except e with _:
re _
fe _e______e___e__________e__

 Replace everything except e with _ using sed:
_e______e___e__________e__