CODEWITHSUNDEEP
regexperl
Fashandge
Fashandge

Reputation: 237

How can I extract a string enclosed in single quotes in Perl?

How do I extract abc from 'abc' using a Perl regular expression?

I tried

echo "'abc'" | perl -ne 'if(/\'(.*)\'/) {print $1}'

but it showed:

-bash: syntax error near unexpected token `('

Upvotes: 4

Views: 2354

Answers (6)

Sam Choukri
Sam Choukri

Reputation: 1904

Precede your single-quoted Perl code with a dollar sign to direct Bash to use an alternate quoting method that turns off shell expansion:

echo "'abc'" | perl -ne $'if(/\'(.*)\'/) {print $1}'

Upvotes: 3

jchips12
jchips12

Reputation: 1227

You need to escape your single quote with ''':

echo "'abc'" | perl -ne 'if( /'\''(.*)'\''/ ){print $1}'

Upvotes: 1

choroba
choroba

Reputation: 241898

This is not a Perl problem; this is a shell problem: you cannot include single quotes into single quotes.

You have to replace each single quote with '\'' (end of single quotes, escaped single quote, and start of single quotes):

echo "'abc'" | perl -ne 'if(/'\''(.*)'\''/) {print $1}'

Upvotes: 7

Kirsten Jones
Kirsten Jones

Reputation: 2706

Well, the cheap way is not to surround your Perl statement with single quotes themselves:

echo "'abc'" | perl -ne "if(/'(.*)'/) {print $1}"

Shell escaping has odd rules...

If you really want to do it the "right" way you can end your first single quoted string, put the quote in, and start another one:

echo "'abc'" | perl -ne 'if(/'\''(.*)'\''/) {print $1}'

Upvotes: 2

daxim
daxim

Reputation: 39158

choroba's answer solves the exact problem. For a generalised solution to any quoting problem, use String::ShellQuote:

                $ alias shellquote='perl -E'\''
                    use String::ShellQuote qw(shell_quote);
                    local $/ = undef;
                    say shell_quote <>;
                '\'''
                $ shellquote
user input →    if(/'(.*)'/) {print $1}␄
perl output →   'if(/'\''(.*)'\''/) {print $1}'

Upvotes: 2

toolic
toolic

Reputation: 62054

You have a shell quoting problem, not a Perl problem.

This is a good use for sed:

echo "'abc'" | sed "s/'//g"

Upvotes: 2

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