Looped sed statement - weird output

Question

I wrote a small script that will recursively go through all *.py files within a directory and replace specific entries in the files.

So the files and their current content:

find . -name "*.py" -exec ls "{}" \; -exec cat "{}" \;

and that returns this:

./1/File1.py
import sys

./2/3/File3.py
import sys
sys.exit(1)

./6/7/File7.py
import sys
sys.exit()

./File0.py
import sys

Now the script I wrote is this:

for file in $(find . -name "*.py")
do
    echo "$file"
    sed 's/sys.exit.*/os_.exit()/g;s/import sys/&\nimport os/g' "$file"
done

Now if I ran those sed commands on their own, I would get my desired output. If I run them both together within my script, or like so:

find . -name "*.py" -exec sed 's/sys.exit.*/os_.exit()/g' "{}" \; -exec sed 's/import sys/&\nimport os/g' "{}" \;

it would end up duplicating my output like this:

./1/File1.py
import sys
import sys
import os

./2/3/File3.py
import sys
os_.exit()
import sys
import os
sys.exit(1)

./6/7/File7.py
import sys
os_.exit()
import sys
import os
sys.exit()

./File0.py
import sys
import sys
import os

Can someone point out what I'm doing wrong?

EDIT: thanks to the link posted by don_crissti, I have edited the script to actually execute a 'one-liner'. I have posted this below, thanks to the input from all who commented it has resolved my issue.

find . -name "*.py" -exec ls "{}" \; -exec sed 's/sys.exit.*/os_.exit()/g;s/import sys/&\nimport os/g' "{}" \;

Why don't you put both edit commands in the same sed invocation? — AlexP, May 11 '18 at 09:52
I agree with @AlexP. I think that will also solve the original problem. — Iskustvo, May 11 '18 at 09:53
Don't loop over find's output.. Other than that your script behaves as expected (that is, sed autoprints all lines, even if no changes were made) — don_crissti, May 11 '18 at 09:54
I noticed that as I hit save. Have fixed it now, thanks. Adding them into the one sed invocation has corrected my issue. How would you recommend a loop over all *.py files to perform these edits in that case? — 64Hz, May 11 '18 at 09:56
Note that you don't actually edit the files. The sed commands as written read a file and output the edited text. If you want to edit the files you need sed -i. — AlexP, May 11 '18 at 09:57
Sorry @AlexP, I meant to add that my script was to test the output before I actually edit them. I will add -i when I am confident it will output correctly. — 64Hz, May 11 '18 at 10:01
@AlexP Since you are the first to propose joining of multiple sed's in one, you should post the official answer. — Iskustvo, May 11 '18 at 10:18

score 1 · Accepted Answer · answered May 11 '18 at 12:15

1

The output is as should be expected, because each of the two sed commands operates on the same unmodified input text. In order to obtain the output which the inquirer expected, the two substitute commands should be combined in one invocation of sed:

... -exec sed -e 's/sys.exit.*/os_.exit()/g' -e 's/import sys/&\nimport os/g' "{}" \;

or

... -exec sed 's/sys.exit.*/os_.exit()/g;s/import sys/&\nimport os/g' "{}" \;

answered May 11 '18 at 12:15

AlexP

10,455

Thank you for the explanation and fix! Much appreciated. – 64Hz May 11 '18 at 12:26

Looped sed statement - weird output

1 Answers1