Re: expr exit status

[Philip Rowlands]

On Wed, 20 Jan 2010, salih k wrote:

> Now shall I explain again (sorry:))
>
> actually the issue is rare and never happened in unix .So am curious on
> this.

"never happened in unix"? Which OS and shell are you using?

> Now my query is why these exit status (254 or 16) are coming during the
> first run then it become correct value after rerun?and
>
> *what does it mean by exit status 16 and 254?Whether this can do any thing
> with expr or issue with *
> */dev/null etc?*

No it can't. The exit status you observe is a bug or a mistake in your 
code or analysis.

> Thats why am asking *whether I can use if [ $? -eq 1 -o $? -eq 2 -o $? -eq 3 ]
> instead of*
>
> *if [ $? -ne 0 ].

No; the apparent exit status greater than 255 is a bug, or a mistake in 
your code or analysis.

> If i should not use if [ $? -eq 1 -o $? -eq 2 -o $? -eq 3 ] then i will go
> ahead with case.But the current expr is a running codew so my manager need
> explanation.thats why.If expr is not stable i have to change all the places
> in script which uses expr.

If it's important to explain your observed usage of expr then I'm not 
sure what to suggest; maybe run the whole script under strace and check 
what arguments for exit() expr is giving, which may hint at the cause of 
the problem.


Cheers,
Phil