topic Shell script debugging in Operating System - HP-UX

Shell script debugging

Paul Remeika — Sun, 17 Apr 2005 07:38:47 GMT

How can I debug a shell script that I have written?

Re: Shell script debugging

Alex Lavrov. — Sun, 17 Apr 2005 07:54:36 GMT

You can execute it with:
sh -x my_script.sh

or change the first line of the script, from:
#!/bin/sh
to
#!/bin/sh -x

If you use sh/bash ofcourse.

Re: Shell script debugging

Victor Fridyev — Sun, 17 Apr 2005 07:55:07 GMT

Hi

You can run it either as
sh -x script
or
insert set -x into the script on the place, which you want to debug

HTH

Re: Shell script debugging

Bill Hassell — Sun, 17 Apr 2005 19:32:17 GMT

A couple of notes about set -x:

It will show each step of your script that was executed (with a + in front of each command) but not exactly line by line. A line that has several commands piped into each other will show each command separately. The if or test statements will be shown but the lines that were not executed won't be shown.

To help with the above scenario, use -x and -v. The -v option shows each line (including comments). Note that because the shell is interpreting the script, the original statements and the trace lines may not always be interleaved together. But it does help see where the script is located during the test run.

Another feature of set -x is that the output goes to stderr. Normally, stdout and stderr go to the screen together, but suppose you want to step through the script one page at a time:

sh -vx myscript | more

What you'll see is all the lines for listing and debugging (immediately) and any of the stdout from the script will go to: | more. To put the two together so that the more command controls all output:

sh -x -v myscript 2>&1 | more

The 2> refers to redirecting stderr and the &1 refers to file descriptor 1 which is stdout. 2>&1 effectively ties both types of output together, so now the more command sees both streams of text.

Re: Shell script debugging

Muthukumar_5 — Mon, 18 Apr 2005 01:10:24 GMT

You can also use set -x and set +x to debug shell script.

#!/bin/ksh
#debug
hostname
# debug starts
set -x
ls
echo bye
set +x
echo over
exit 0

HTH.

Re: Shell script debugging

f. halili — Mon, 18 Apr 2005 07:47:53 GMT

# ksh -x script.ksh
or
# sh -x script.sh

- f. halili