OT: bash help

[Fred Smith]

On Sat, Aug 16, 2014 at 02:44:14PM -0700, Mike Wright wrote:
> Hi all,
> 
> I'm trying to write a simple script that if provided an argument,
> uses that, or if nothing is provided, uses a predefined string.
> 
> if [ -n $# ]
> then
>     WORDS=$1
> else
>     WORDS="these are some words"
> fi
> echo $WORDS;
> 
> The second case is always comes back "".
> 
> But if I write
> 
> WORDS='these are some words'
> echo $WORDS
> 
> I get the assigned string.
> 
> Why doesn't the assignment work when inside an if/then?  How do I
> make it work?  What's the difference between the case where the
> assignment is inside the if/then and outside the if/then?

This works:

	#!/bin/sh
	if [ $# -ne 0 ]
	then
	    WORDS=$1
	else
	    WORDS="these are some words"
	fi
	echo $WORDS

the hashbang line should be used, but doesn't actually change the
output of this script.

"$#" is an integer, not a string, and that it should therefore be tested
as an integer and not a string, hence the if statement being:

	if [ $# -ne 0 ]

and you don't NEED the quotes around the literal string, though
it doesn't harm to put them there, perhaps as documentation to make
clear what you intention is.


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