How to make sed read its script from a file?

Question

Recently I came across following grep command:

/usr/xpg4/bin/grep -Ff grep.txt input.txt > output.txt 

which as per my understanding means that from input.txt, grep the matter contained in grep.txt and output it to output.txt.

I want to do something similar for sed i.e. I want to keep the sed commands in a separate file (say sed.txt) and want to apply them on input file (say input.txt) and create a output file (say output.txt).

I tried following:

/usr/xpg4/bin/sed -f sed.txt input.txt > output.txt 

It does not work and I get the following error:

sed: command garbled 

The contents of files mentioned above are as below:

sed.txt

sed s/234/acn/ input.txt sed s/78gt/hit/ input.txt 

input.txt

234GH 5234BTW 89er 678tfg 234 234YT tfg456 wert 78gt gh23444 

Answer 1

Your sed.txt should only contain sed commands: No prefixing with sed or suffixing with an input file. In your case it should probably be:

# sed.txt s/234/acn/ s/78gt/hit/ 

When ran on your input:

$ /usr/xpg4/bin/sed -f sed.txt input.txt 

 acnGH 5acnBTW 89er 678tfg acn acnYT tfg456 wert hit ghacn44 

Answer 2

Rather than keeping the sed commands in a separate text file, you may want to try creating a sed script. The file below can run directly on your data files:

./myscript.sed inputfile.txt > outputfile.txt

#!/bin/sed -f s/234/acn/ s/78gt/hit/