Running set options from the command line and bash command


 
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# 1  
Old 07-27-2011
Running set options from the command line and bash command

I'm reading about debugging aids in bash and have come across the set command. It says in my little book that an addition to typing

set [option]

you can also use them "on the command line when running a script..." and it lists this in a small table:


set -o option Command Line option
noexec -n
verbose -v
xtrace -x

I know how to set the options in the first column, but how are the options in the second column used? I've tried typing the name of the script followed by the option and vice versa, but only the results of the script are displayed on the screen. Can someone tell me what I'm doing wrong, or am I misunderstanding something?

The book I'm using is "Learning the bash shell" if that helps, 3rd edition, page 222 halfway down under "set options"

Also, on the following page, when illustrating how to find a bug in program, it lists the command

bash -v scriptname

when looking for the bug.

what does the command bash do exactly? I haven't encountered this command before in this context and am not sure what's going on.
# 2  
Old 07-27-2011
Quote:
Originally Posted by Straitsfan
I know how to set the options in the first column, but how are the options in the second column used?
for example, set -n
# 3  
Old 07-27-2011
Hey there,

I'm not quite sure about your first question, however to debug a bash shell script the command is thus;

# bash -x <script name>
# 4  
Old 07-27-2011
Corona --

What I meant was on the command line you can use set [option as a word] to turn it on or off, and then run a script to see the results. But what I was wondering is how to use the other option on the command line. I tried

set -v testscript

and nothing happened (it works fine if I type set -o verbose testscript, for example.] If I tried the scriptname first and then the one letter option, I get an error message. So I was confused as to how to use just the one letter option on the command line -- or is that how it's done when you use the command bash?

I hope that's clearer.

And what exactly does the command 'bash' do?
# 5  
Old 07-27-2011
Quote:
Originally Posted by Straitsfan
Corona --

What I meant was on the command line you can use set [option as a word] to turn it on or off, and then run a script to see the results. But what I was wondering is how to use the other option on the command line. I tried

set -v testscript

and nothing happened (it works fine if I type set -o verbose testscript, for example.] If I tried the scriptname first and then the one letter option, I get an error message. So I was confused as to how to use just the one letter option on the command line -- or is that how it's done when you use the command bash?

I hope that's clearer.

And what exactly does the command 'bash' do?
Hi you asked how to find a bug / debug a script, if it's a bash script then the command would be;

# bash -x scriptname.bash

korn shell script

# ksh -x scriptname.ksh

etc

William
# 6  
Old 07-28-2011
Quote:
Originally Posted by Straitsfan
set -v testscript
set works inside a shell, it doesn't change options for another shell, or options for a program which hasn't even been run yet.
 
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