Perl + one-liner smart Perl command, in place grep to match unusual characters + full match

Question

Subject: one-liner smart Perl command instead of a simple grep (in Bash script)

I have a problem when I use grep to match the unusual characters (I can\'t put the \"\\\"

Answer 1

I'm not sure I understand your question, exactly. Perhaps -P and -x do what you want, along with quoting "$Some_string" to preserve whitespace?

grep -Px "$Some_string" file

From the grep man page:

-P, --perl-regexp

Interpret PATTERN as a Perl regular expression.

-x, --line-regexp

Select only those matches that exactly match the whole line.

Answer 2

You could do something like this:

perl -ne 'print if m|\Q[ * ( & % \E\@\Q !]\E|' file

I've found the \Q and \E operator in Quote and Quote-like Operators.

A snippet from that link:

You cannot include a literal $ or @ within a \Q sequence. An unescaped $ or @ interpolates the corresponding variable, while escaping will cause the literal string \$ to be inserted. You'll need to write something like m/\Quser\E@\Qhost/.

\Q  Quote (disable) pattern metacharacters till \E or
    end of string

\E  End either case modification or quoted section
    (whichever was last seen)

Answer 3

You will have to escape the string somehow. Using \ to escape special characters is required in this case, because passing the string to Perl is really no different than passing it to grep -- both will see the string after the shell processes it.

Using Perl to do this will simply obfuscate your code.