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Regular expression matching in BASH (equivalent of =~ in Perl)


 
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# 1  
Old 07-27-2009
Regular expression matching in BASH (equivalent of =~ in Perl)

In Perl I can write a condition that evaluates a match expression like this:

if ($foo =~ /^bar/) {
do blah blah blah
}

How do I write this in shell? What I need to know is what operator do I use? The '=~' doesn't seem to fit. I've tried different operators, I browsed the man page for bash and I Google'd but I can't seem to figure this out.

Thanks!
# 2  
Old 07-27-2009
Are you sure you are using version 3 or newer of bash?
To see which version you are using, do the following:

Code:
echo $BASH_VERSINFO

There is some example code at
Bash Regular Expressions | Linux Journal

If you don't have version 3 of bash, see ":" operator in the expr man page:
expr(1): evaluate expressions - Linux man page

You can also use the "case" statement in bash to do matching, but filename matching rules are used instead of regular expression rules.
# 3  
Old 07-27-2009
regex doesn't support in condition prior to bash3.0.

one way :

Code:
found=$(echo $foo | grep '^bar')
if [ "$found" ]; then
 do something
else
 do something else
fi

# 4  
Old 07-27-2009
Thank you.
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