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bug#22045: expr substr returns with an error code 1 when the substring s
From: |
Pádraig Brady |
Subject: |
bug#22045: expr substr returns with an error code 1 when the substring starts with 0 |
Date: |
Sat, 28 Nov 2015 23:34:05 +0000 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 |
tag 22045 notabug
close 22045
stop
On 28/11/15 20:47, Matthias Klose wrote:
> found with coreutils-8.23, expr substr returns with an error code when the
> substring consists of only '0' characters, and the match is started at
> position 1.
>
> $ expr substr 00001234 3 4; echo $?
> 0012
> 0
> $ expr substr 1234 1 2; echo $?
> 12
> 0
>
> $ expr substr 00001234 1 2; echo $?
> 00
> 1
> $ expr substr 00001234 1 4; echo $?
> 0000
> 1
> $ expr substr 00001234 1 5; echo $?
> 00001
> 0
This is a common gotcha. POSIX states that:
exit status of 1 is used if "the expression evaluates to null or zero".
I must collate some gotchas like this.
cheers,
Pádraig.