In a bash script echo shell commands

Question

In a bash script how do I echo all shell commands called and expand any variable names? For example, given the following line:

ls $DIRNAME

I would like the script to run the command and display the following

ls /full/path/to/some/dir

The purpose is to save a log of all shell commands called and their arguments. Perhaps there is a better way of generating such a a log?

Answer 1

set -o verbose, or set -v, set -x seems to be the way

http://www.faqs.org/docs/abs/HTML/options.html

$ cat shl
#!/bin/bash                                                                     

DIR=/tmp/so
ls $DIR

$ bash -x shl 
+ DIR=/tmp/so
+ ls /tmp/so
$

Answer 2

set -x will give you what you want.

Here is an example shell script to demonstrate:

#!/bin/bash
set -x verbose #echo on

ls $PWD

This expands all variables and prints the full commands before output of the command.

output:

+ ls /home/user/
file1.txt file2.txt