Add string with backslash in file using sed command

Question

I need to add a text string:

--with-mpm=event \

to httpd.spec on 138th position.

I tried:

sed -i '138i--with-mpm=event \\' /root/rpmbuild/SPECS/httpd.spec

This code runs in bash script of Vagrantfile during bootstrapping virtual machine. However, the script returns error.

When I check httpd.spec, output is a string missing backslash:

--with-mpm=event

It works okay running it directly in shell of virtual machine though.

How can I fix it with sed?

Thanks!

Usually, try adding up backslashes until you get them. ``\\\``? ``\\\\``? — Wiktor Stribiżew, Feb 23 '19 at 15:17
Thanks, i added plus two backslashes in code and it fixed issue. It helps. I can note your answer like right! — ERemarque, Feb 23 '19 at 16:02

score 2 · Accepted Answer · answered Feb 23 '19 at 16:14

The rule of thumb when dealing with backslashes is keep adding up backslashes until you get the expected result.

In this case, a literal backslash here needs to be coded with four backslashes:

sed -i '138i--with-mpm=event \\\\' /root/rpmbuild/SPECS/httpd.spec

1 Answers1