helpThe GNU Bourne-Again SHell - Support: sr #110463, operator '=~' condition is wrong

 
 

sr #110463: operator '=~' condition is wrong

Submitted by:  Kory Chiu <korychiu>
Submitted on:  Tue 23 Mar 2021 07:43:40 AM UTC
 
Category:  None Priority:  5 - Normal
Severity:  3 - Normal Status:  Invalid
Privacy:  Public Assigned to:  None
Open/Closed:  Open Operating System:  GNU/Linux
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Tue 30 Mar 2021 02:39:48 AM UTC, comment #2: 

Thanks for the correction.

Kory Chiu <korychiu>
Thu 25 Mar 2021 07:06:03 PM UTC, comment #1: 

Your usage is wrong. AND-OR lists are not a straight substitute for if statements. They are left-associative and have equal precedence.

This means that your first example is equivalent to

{ [[ "$_config" =~ "vhodddst.conf" ]] || echo "false" ; } && echo "true"

Since the group command returns the status of the echo command, the command returns success and the command to the right of the && gets executed.

In the original example, then, the exit status of the OR list is the exit status of the echo, and, since that is successful, the rest of the AND list is executed.

You should be able to follow the execution of your second example to see why it differs.

Chet Ramey <chet>
Project Administrator
Tue 23 Mar 2021 07:43:40 AM UTC, original submission:  

# _config="vhost.conf"

# [[ "$_config" =~ "vhodddst.conf" ]] || echo "false" && echo "true"
false
true

# [[ "$_config" =~ "vhost.conf" ]] || echo "false" && echo "true"
true

# [[ "$_config" =~ "vhodddst.conf" ]]
# echo $?
1

bash --version
GNU bash, version 5.0.17(1)-release (x86_64-pc-linux-gnu)
Copyright (C) 2019 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>

This is free software; you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Kory Chiu <korychiu>

 

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    Follows 1 latest change.

    Date Changed by Updated Field Previous Value => Replaced by
    2021-03-25 chet StatusNone => Invalid

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