Substitution in text file without regular expressions

export FIND='find this'
export REPLACE='replace with this'
ruby -p -i -e "gsub(ENV['FIND'], ENV['REPLACE'])" path/to/file

This is the only 100% safe solution here, because:

It's a static substition, not a regexp, no need to escape anything (thus, superior to using sed)
It won't break if your string contains } char (thus, superior to a submitted Perl solution)
It won't break with any character, because ENV['FIND'] is used, not $FIND. With $FIND or your text inlined in Ruby code, you could hit a syntax error if your string contained an unescaped '.

When you don't need the power of regular expressions, don't use it. That is fine.
But, this is not really a regular expression.

sed 's|literal_pattern|replacement_string|g'

So, if / is your problem, use | and you don't need to escape the former.

PS: About the comments, also see this Stackoverflow answer on Escape a string for sed search pattern.

Update: If you are fine using Perl try it with \Q and \E like this,

 perl -pe 's|\Qliteral_pattern\E|replacement_string|g'

_{@RedGrittyBrick has also suggested a similar trick with stronger Perl syntax in a comment here or here}

The replace command will do this.

https://linux.die.net/man/1/replace

Change in place:

replace text replacement -- path/to/the/file

To stdout:

replace text replacement < path/to/the/file

Example:

$ replace '.*' '[^a-z ]{1,3}' <<EOF
> r1: /.*/g
> r2: /.*/gi
> EOF
r1: /[^a-z ]{1,3}/g
r2: /[^a-z ]{1,3}/gi

The replace command comes with MySQL or MariaDB.

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