BASH script syntax check, track execution?

As a (Debian) Linux newbie I was wondering if there is a way to track the execution of a bash shell (.sh) script ? Like in Windows you trigger that with a echo on command in a batch file.

My first 'unix' script ever, but I'm wondering if it will run as expected :

#!/bin/bash
# switch maintenance mode off and go live with your ownCloud
occpath='/var/www/owncloud'
htuser='www-data'
alias occ-do=sudo -u $htuser php $occpath/occ
echo info: Switching to live-mode ..
occ-do maintenance:mode --on` 

the line I'm trying to create is like sudo -u www-data php /var/www/owncloud/occ (occ is what should be executed, let's assume I don't need a path for the php part).

Will this work; any mistakes in the syntax? And let's not forget my question about the execution following ..

3 Answers

Is there is a way to track the execution of a bash shell (.sh) script?

You can use set -x, set +x and set -v as described below.

• set -x : Display commands and their arguments as they are executed.
• set +x : Turn off debugging
• set -v : Display shell input lines as they are read.

HowTo: Debug a Shell Script Under Linux or UNIX

1. Use -x option to debug a shell script

Run a shell script with -x option.

$ bash -x script-name
$ bash -x domains.sh

2. Use of set builtin command

Bash shell offers debugging options which can be turn on or off using set command.

• set -x : Display commands and their arguments as they are executed.
• set -v : Display shell input lines as they are read.

You can use above two commands in shell script itself:

#!/bin/bash
clear
# turn on debug mode
set -x
for f in *
do file $f
done
# turn OFF debug mode
set +x
ls
# more commands

You can replace the standard Shebang line:

#!/bin/bash

with the following (for debugging) code:

#!/bin/bash -xv

Source HowTo: Debug a Shell Script Under Linux or UNIX

Further Reading

• An A-Z Index of the Bash command line for Linux - An excellent reference for all things Bash command line related.
• set - Manipulate shell variables and functions.

Put

set -x

at the point where you want debug info start to showand

set +x

where you want it off. I don't promise what you see will always be straightforward but you can get used to id after a while.

This is the simple way to check the syntax of your shell scripts :

Here in this website, the online syntax checker marks the line & displays the error which is caused due to incorrect syntax

As per the suggestion from other answers, you can try set -x & set +x to enable & disable debug mode respectively for tracking the execution of script.