Bash bug?

[Steven W. Orr]

On Monday, Sep 26th 2005 at 07:12 +0200, quoth Zoltan Boszormenyi:

=>Hi,
=>
=>I am trying something like the following,
=>with a configuration file containing a token and
=>a directory in a line, depending on the tokens,
=>certain actions should be taken later. Validating
=>the configuration file whether all the required/optional
=>tokens are in the file should go like this:
=>
=>-----a.txt----------------------
=>A directory1
=>B directory2
=>C directory3
=>--------------------------------
=>
=>-----a.sh-----------------------
=>#!/bin/bash
=>
=>HAS_A=0
=>HAS_B=0
=>HAS_C=0
=>cat a.txt | while read i ; do
=>        if [ "`echo $i | awk '{ print $1 }'`" = "A" ]; then
=>                HAS_A=1
=>        fi
=>        if [ "`echo $i | awk '{ print $1 }'`" = "B" ]; then
=>                HAS_B=1
=>        fi
=>        if [ "`echo $i | awk '{ print $1 }'`" = "C" ]; then
=>                HAS_C=1
=>        fi
=>        echo "A: $HAS_A B: $HAS_B C: $HAS_C"
=>done
=>echo "Final A: $HAS_A B: $HAS_B C: $HAS_C"
=>--------------------------------

#!/bin/bash

HAS_A=0
HAS_B=0
HAS_C=0
while read lbl dir
do
    [[ $lbl = A ]] && HAS_A=1
    [[ $lbl = B ]] && HAS_B=1
    [[ $lbl = C ]] && HAS_C=1
    echo "A: $HAS_A B: $HAS_B C: $HAS_C"
done < a.txt
echo "Final A: $HAS_A B: $HAS_B C: $HAS_C"

cat | while causes the while to be in a subshell.

=>Result is:
=>
=>--------------------------------
=>$ ./a.sh
=>A: 1 B: 0 C: 0
=>A: 1 B: 1 C: 0
=>A: 1 B: 1 C: 1
=>Final A: 0 B: 0 C: 0
=>--------------------------------


-- 
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steveo at syslang.net