[SOLVED] Bash script character range loop syntax

OrigBitmancer · 2020-07-08 20:57:09

I cannot remember my basic bash. Please help.

Given a set of files, file_#.text, where # is selected from [ABCDEFGHJKLMNPQ], a closed set of known letters,
how do I write a loop executing once per letter?

I would check my loop by the statement

  echo process1 file_#.text otherfile_#.text

to make sure the substitution is correct,
(where what will execute when finished is "process1 file_#.text otherfile_#.text").

Last edited by OrigBitmancer (2020-07-09 01:56:08)

jasonwryan · 2020-07-08 21:14:12

for x in *.text; do the_thing "$x"; done

Trilby · 2020-07-08 21:44:21

JWR, the simple for loop would not acheive the main goal of having that letter in both arguments to the process.

The direct answer to your question is this:

for N in A B C D E F G H J K L M P Q; do
   process1 file_${N}.text otherfile_${N}.text
done

But if you are not exactly sure what the letters are, or if they may change, the following more flexible approach might be better:

for fname in file_*.text; do
   process1 $fname otherfile_${fname#file_}
done

EDIT: looking back on this, the command in my second loop is pretty silly, this would have the same result:

   process1 $fname other${fname}

Last edited by Trilby (2020-07-09 02:12:50)

OrigBitmancer · 2020-07-09 01:55:44

Trilby wrote:

JWR, the simple for loop would not acheive the main goal of having that letter in both arguments to the process.
The direct answer to your question is this:
for N in A B C D E F G H J K L M P Q; do
   process1 file_${N}.text otherfile_${N}.text
done
But if you are not exactly sure what the letters are, or if they may change, the following more flexible approach might be better:
for fname in file_*.text; do
   process1 $fname otherfile_${fname#file_}
done

Thank you very much! Your first solution did the trick. It was a mistake in my punctuation in my source.

Not quite sure why the other reply was unhelpful?

Last edited by OrigBitmancer (2020-07-09 01:56:41)

jasonwryan · 2020-07-09 02:08:47

OrigBitmancer wrote:

Not quite sure why the other reply was unhelpful?

I had misunderstood your requirements; I thought you just wanted to loop over a set of files.

Arch Linux

#1 2020-07-08 20:57:09

[SOLVED] Bash script character range loop syntax

#2 2020-07-08 21:14:12

Re: [SOLVED] Bash script character range loop syntax

#3 2020-07-08 21:44:21

Re: [SOLVED] Bash script character range loop syntax

#4 2020-07-09 01:55:44

Re: [SOLVED] Bash script character range loop syntax

#5 2020-07-09 02:08:47

Re: [SOLVED] Bash script character range loop syntax

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