How to use sed on a literal string containing regex meta characters?

Question

I want to delete the lines from a file which match an arbitrary literal string.
The string is contained in a variable, and may itself contain various regex meta characters such as [,],^,$,|, etc
So, my problem is that sed wants to interpret these meta characters itself. For example:
x='abc[xyz$'
sed -i "/$x/d" file
produces a sed error about the unmatched [, and no doubt it wants to interpret the $ too.
(Of course, I could try and change the string $x so that every possible regex meta character was escaped with a \, but that seems immensely cumbersome. Also, can't see a way of using single or double quotes cleverly.)
Sorry if I am being thick about this, but any ideas or alternative methods would be most welcome!

Answer 1

frostschutz wrote:
With sed, you have to escape meta characters indivudually. That's just how it works. Of course you could do the escaping using sed as well, by replacing all meta characters (including \ and /) with \character.
If you want to match strings literally, use a different tool. Or do it in Bash.
while read line
do
[ "$line" != "$x" ] && echo "$line"
done < file
In Perl/PCRE instead of escaping indivudually there is \Q...\E but sed does not understand that, and \Q\E does not solve all problems either, if there is a \E in the $x you have to escape it with \E\\E\Q or something like it.
Thank you for your swift reply. Looks like sed can't be much of a friend in these circumstances!
Probably will have to go with the Bash file handling method.
Oh well ...