Shell syntax


 
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# 1  
Old 10-06-2008
Shell syntax

I'm having simple question here, [ "${OS}"x = "SunOS"x ] and [ "${OS}" = "SunOS" ] what's the different here? What is the "x" for? Thanks!
# 2  
Old 10-06-2008
i don't think it stands for something.
# 3  
Old 10-06-2008
Quote:
Originally Posted by vidyadhar85
i don't think it stands for something.
I guess there must be a reason since it exists on lots of the scripts. But I never used that.
# 4  
Old 10-06-2008
did you experienced any difference when its not there??
# 5  
Old 10-06-2008
Quote:
Originally Posted by vidyadhar85
did you experienced any difference when its not there??
No, that's why I'm posting here. If you take look any commercial scripts, you will see that a lot in while, if statements.
# 6  
Old 10-06-2008
Quote:
Originally Posted by redstone
No, that's why I'm posting here. If you take look any commercial scripts, you will see that a lot in while, if statements.

I've never seen it used in while or if statments. I've seen it in test statements ([ is synonymous with test) and in arguments to expr.

When I have seen it, it has never been used the way you show it; the X is placed before the variable or string.

It is done to avoid ambiguity (e.g., when the value begins with a hyphen) or an empty string.
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