Debugging shell scripts with line numbers

Question

I inherited a over 700 line shell script and noticed that when I ran the script it spits out error at some point of execution.

E.g error that I see on the console is something like

cat: /Wreck/wreck_module.rb: No such file or directory

I have tried to use set -x and most of the tips from this link, however I noticed that all the output that I was getting were pretty noisy.

Is there a way to get the exact line number of where a shell command returned a non-zero status?

What shell are you using exactly? – John Zwinck Jul 06 '13 at 03:22 — John Zwinck, Jul 06 '13 at 03:22
Use `bash -vx` to execute your shell script – Basile Starynkevitch Jul 06 '13 at 06:16 — Basile Starynkevitch, Jul 06 '13 at 06:16

score 4 · Accepted Answer · answered Jul 06 '13 at 03:36

4

Put this at the top of the script you want to debug:

#!/bin/bash
function trace_line(){
  caller
}
trap trace_line debug

and perhaps redirect the output to a file for easy analysis.

answered Jul 06 '13 at 03:36

perreal

What does this do? Is "caller" a built-in shell feature? Edit: [yes, it is.](http://unix.stackexchange.com/q/19323) – Torben Gundtofte-Bruun Dec 09 '14 at 12:19
When I put it in the first few lines of the script, it seems that it cannot print the line number in the **function**, how can I modify it – moluzhui Jun 17 '23 at 07:26

1 Answers1