Replacing multiple strings in multiple files

Question

I have a file containing a list of regular expressions and replacement literal strings in the following format :

OLD_REGEXP_1 NEW_STRING_1
OLD_REGEXP_2 NEW_STRING_2
...

I want to replace all of the strings that match OLD_REGEXP_X with NEW_STRING_X in multiple files *.txt.

I believe that this is a common question and someone should have already done something similar before, but I just couldn't find an existing solution written in bash.

For example :

Tom Thompson
Billy Bill&Ted
goog1e\.com google.com
https?://www\.google\.com https://google.com

Input :

Tom and Billy are visiting http://www.goog1e.com

Expected output :

Thompson and Bill&Ted are visiting https://google.com

The major challenges are :

• The strings to be replaced are described by POSIX Extended Regular Expressions, not literal, and any character that is not a POSIX ERE metacharacter, including / which is often used as a regexp delimiter by some tools, must be treated as literal.
• The replacement strings are literal and can contain any literal character, including chars like & and \1 that are often used as backreference metacharacters in replacement strings but must be literal in this case.
• Replacements must occur in the order they appear in the mapping file so if we have A->B and B->C in that order in the mapping file and A appears in the text file that is to be changed, then the output will contain "C" in place of "A", not "B".

Answer 1

You can convert your substitution list file into a sed script file, then let sed do the job for you.

give this a try with gnu sed:

sed -i -f <(sed -r 's/^(\S*) (.*)/s@\1@\2@/g' listfile) *.txt