For i in loop on file uses filename as well

Question

So here is my problem when using code:

for i in filename.txt
do
    <operations>
    done

Operations are being made on both file contents as well as filename itself, why is that happening?

Just to be clear I alread got 2 solutions that solve this problem, but I still can't understand why is that happening. One of the solutions that have worked for me:

for i in $(cat filename.txt)
do
    tar -czf ${i}.tar $i
rm -R $i
gzip $i.tar
    done

In `for i in filename.txt` you will have one `$i` and it will be set to `filename.txt`. What are you asking about exactly? — Ted Lyngmo, Jul 15 '20 at 17:55
Ted- No, in filename.txt there is list that is used in for loop. I want to read every line in that file and do operations(packing, removing etc.) on them and it works exactly like that except it also does operation on "filename.txt" itself as well. — Michał Broda, Jul 15 '20 at 18:08
https://stackoverflow.com/q/1521462 https://stackoverflow.com/a/37210472 — alecxs, Jul 15 '20 at 18:09
Then you should do: `while read -r line; do ...operations using $line... ; ...etc...; done < file.txt` — M. Nejat Aydin, Jul 15 '20 at 18:12
You need a [mcve]. Don't just brush aside the body of the loop with ``. Provide an *actual* body that reproduces the problem you are seeing. — chepner, Jul 15 '20 at 18:49
@MichałBroda Yes. In `for i in filename.txt` you will have one `$i` and it will be set to `filename.txt`. If you want to read the contents of `$i` - do that in the loop. — Ted Lyngmo, Jul 15 '20 at 23:28

score 0 · Answer 1 · answered Jul 16 '20 at 12:07

0

"Yes. In for i in filename.txt you will have one $i and it will be set to filename.txt. If you want to read the contents of $i - do that in the loop." Thank you Ted Lyngmo.

answered Jul 16 '20 at 12:07

Michał Broda

1
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For i in loop on file uses filename as well

1 Answers1