UNIX for Dummies Questions & Answers

VAR=123456:abcdeg
VAR2=`echo $VAR | sed y/:/\ /`

first()
{
   return $1
}

VAR3=`first $VAR2`

# VAR="abc:123"
# echo ${VAR##*:}
123
# echo ${VAR%%:*}
abc

# echo $VAR | awk -F: '{print $1}'
abc
# echo $VAR | sed 's/:.*//'
abc

#!/usr/bin/env sh

# @(#) s1       Demonstrate string extraction from variable.

set -o nounset
echo

debug=":"
debug="echo"

## Use local command version for the commands in this demonstration.

echo "(Versions displayed with local utility \"version\")"
version >/dev/null 2>&1 && version bash expr

echo

VAR="123456:abcdeg"
echo " Goal: extract text before : from \"$VAR\""

echo
echo " Old school with expr string matching:"
expr $VAR : "\(.*\):"

echo
echo " bash / ksh parameter expansions:"
echo ${VAR%%:*}
echo ${VAR//:*}

exit 0

% ./s1

(Versions displayed with local utility "version")
GNU bash 2.05b.0
expr (GNU coreutils) 5.2.1

 Goal: extract text before : from "123456:abcdeg"

 Old school with expr string matching:
123456

 bash / ksh parameter expansions:
123456
123456

echo
echo " Setting the argument vector:"
oldIFS="$IFS"
IFS=":"
set -- $VAR
IFS="$oldIFS"
echo " First argument is \"$1\""

 Setting the argument vector:
 First argument is "123456"