Advanced Bash−Scripting Guide

Advanced Bash−Scripting Guide
Example 10−26. Using command substitution to generate the case variable
#!/bin/bash
# Using command substitution to generate a "case" variable.
case $( arch ) in # "arch" returns machine architecture.
i386 ) echo "80386−based machine";;
i486 ) echo "80486−based machine";;
i586 ) echo "Pentium−based machine";;
i686 ) echo "Pentium2+−based machine";;
* ) echo "Other type of machine";;
esac
exit 0
A case construct can filter strings for globbing patterns.
Example 10−27. Simple string matching
#!/bin/bash
# match−string.sh: simple string matching
match_string ()
{
MATCH=0
NOMATCH=90
PARAMS=2 # Function requires 2 arguments.
BAD_PARAMS=91
}
[ $# −eq $PARAMS ] || return $BAD_PARAMS
case "$1" in
"$2") return $MATCH;;
* ) return $NOMATCH;;
esac
a=one
b=two
c=three
d=two
match_string $a # wrong number of parameters
echo $? # 91
match_string $a $b # no match
echo $? # 90
match_string $b $d # match
echo $? # 0
exit 0
Chapter 10. Loops and Branches 120