Conflict between variable substitution and CJK characters in BASH
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AndreasT
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Published on 2012-12-13T13:58:19Z
Indexed on
2012/12/14
11:20 UTC
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bash
I encountered a problem with variable substitution in the BASH shell.
Say you define a variable a
. Then the command
$> echo ${a//[0-4]/}
prints its value with all the numbers ranged between 0 and 4 removed:
$> a="Hello1265-3World"
$> echo ${a//[0-4]/}
Hello65-World
This seems to work just fine, but let's take a look at the next example:
$> b="?1265-3?"
$> echo ${b//[0-4]/}
?1265-3?
Substitution did not take place: I assume that is because b
contains CJK characters. This issue extends to all cases in which square brackets are involved. Surprisingly enough, variable substitution without square brackets works fine in both cases:
$> a="Hello1265-3World"
$> echo ${a//2/}
Hello165-3World
$> b="?1265-3?"
$> echo ${b//2/}
?165-3?
Is it a bug or am I missing something?
I use Lubuntu 12.04, terminal is lxterminal
and echo $BASH_VERSION
returns 4.2.24(1)-release.
EDIT: Andrew Johnson in his comment stated that with gnome-terminal
4.2.37(1)-release the command works fine. I wonder whether it is a problem of lxterminal
or of its specific 4.2.24(1)-release version.
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