Question

I have a bunch of files and a script which I run on them. That script takes 2 files as an input and all files are in this format: a.txt1 a.txt2

Now the script I use is like this: foo.sh a.txt1 a.txt2

I have to run this script run on 250 pairs (eg. a1.txt1 a1.txt2 to a250.txt1 a250.txt2)
I am doing this manually by entering file names. I was wondering is there any way to automate this process. All these pairs are in same folder, is there any way to loop the process on all pairs?

I hope I made it clear.

Thank you.

To be specific, these are some sample file names:

• T39_C.txt2
• T39_D.txt1
• T39_D.txt2
• T40_A.txt1
• T40_A.txt2
• T40_B.txt1
• T40_B.txt2
• T40_C.txt1
• T40_C.txt2
• T40_D.txt1
• T40_D.txt2
• unmatched.txt1
• unmatched.txt2
• WT11_A.txt1
• WT11_A.txt2
• WT11_B.txt1
• WT11_B.txt2
• WT11_C.txt1

Answer 1

Assuming all files are in pairs (ie, <something>.txt1 and <something>.txt2 then you can do something line this:

1. #!/bin/bash
2.
3. for txt1 in *.txt1; do
4.    txt2="${txt1%1}2"
5.    # work on $txt1 and $txt2
6. done

In line 3, we use a shell glob to grab all files ending with .txt1. Line 4, we use a substitution to remove the final 1 and replace it with a 2. And the real work is done in line 5.