Putting a Perl variable in awk command

Question

In Perl, I'm trying to search a txt file for a string that the user inputs and print out every line that where the string is found.

Here is what I have

my $input = <STDIN>;
print `sed -n "/$input/p" inputfile.txt`;

I'm getting this error: sed -e expression #1, char 9: unterminated address regex

Could anyone help me out with this?

The best help would be not to use sed inside Perl. Perl can do that easily. — TLP
– TLP, Commented Mar 10, 2015 at 2:56
Also, that might feel like a neat trick to do, but it is very dangerous. You are allowing users to execute arbitrary code on your system. (E.g. use "; rm -rf / as input.) Even if you trust them, things can happen by mistake. — TLP
– TLP, Commented Mar 10, 2015 at 3:02

Andy Lester · Accepted Answer · 2015-03-10 04:04:25Z

4

Don't shell out to sed to do what Perl can do for you.

my $input = <STDIN>;
chomp $input;
open my $fh, '<', 'inputfile.txt' or die $!;
while ( <$fh> ) {
    print if /$input/;
}

answered Mar 10, 2015 at 2:57

Andy Lester

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2 Comments

Hmm.. I tried this and I'm getting no result when I enter something to search. No errors but no result too.

@JimDavis Yup, you're right lol. Thank you. I'm just learning scripting languages and they're so much more of a pain than learning Java or C++.