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Home > Forums > Programmers > Languages > UNIX Scripting Forum

preserving a variable inside a while loop subshellHelpful Member! 

thread822-1615596
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exsnafu (TechnicalUser)
10 Aug 10 13:14
I set the value of $port outside of a while loop

read in a file and pull two variable out of it, sometimes the second variable(port) is set, sometimes not.. but if not, then i want it to have a default value

seems to be the only way i can solve this is by explicitly checking for $port on each line and if its empty, set it inside the while loop.. any way to preserve the global value of $port in the loop?

CODE

#!/bin/bash
export port=161
export file=~/test1

while read server port; do
        echo "devcreate ${server%%.*} $server $port"
done < $file

contents of test1:

CODE

fqdn1.hostname.com
fqdn2.hostname.com
fqdn3.hostname.com 4161
fqdn4.hostname.com 161
fqdn5.hostname.com 4161
 
Helpful Member!  LKBrwnDBA (MIS)
10 Aug 10 14:07


Try this:

CODE

#!/bin/bash
export dport=161
export file=~/test1

while read server port;
do
  echo "devcreate ${server%%.*} $server ${port:-$dport}"
done < $file
3eyes

----------------------------------------------------------------------------
The person who says it can't be done should not interrupt the person doing it. -- Chinese proverb
 
exsnafu (TechnicalUser)
10 Aug 10 14:37
aha, thanks.. i reversed the use but same difference.. this way i can keep $port as the global and have a new var just for the one offs inside the loop.

CODE

while read server nport; do
        echo "devcreate ${server%%.*} $server ${nport:-$port}"
done < $file



 
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