issue while assigning values to variables in for loop |bash

Question

I am getting command not found error for code below:

#!/bin/sh
#set -x
for i in `cat  output`;
do
eval "MASTER_$i = $(/usr/efm-2.0/bin/efm cluster-status $i 2>/dev/null |grep "Master"  |head -1 |awk -F " " {'print$2'})";
echo -e "$MASTER_$i";
done

Debug output is:

./test.sh
++ cat output
+for i in '`cat  output`'
++ /usr/efm-2.0/bin/efm cluster-status abc
++ grep Master
++ head -1
++ awk -F ' ' '{print$2}'
+eval 'MASTER_abc = 10.x.x.x'
++ MASTER_abc = 10.x.x.x
**./test.sh: line 5: MASTER_abc: command not found**
+echo -e abc
abc

You aren't iterating over the lines of your file; you are iterating over the whitespace-separated words resulting from the contents of your file being subjected to pathname expansion. See Bash FAQ 001. — chepner
– chepner, Commented Aug 24, 2017 at 22:22

blackghost · Accepted Answer · 2017-08-24 18:32:05Z

2

You have spaces around the =... If you try running eval "i = 1", it will try running command i, with parameters = and 1 instead of setting i to be 1.

answered Aug 24, 2017 at 18:32

blackghost

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Comments

glenn jackman · Accepted Answer · 2017-08-24 18:45:08Z

1

Strongly recommend you use a bash associative array instead of dynamic variable names:

#!/bin/bash
#set -x
declare -A master
while IFS= read -r line; do
    master["$line"]=$( /usr/efm-2.0/bin/efm cluster-status "$line" 2>/dev/null |awk '/Master/ {print $2; exit}' )
done < output.file

for line in "${!master[@]}"; do
    printf "%s\t%s\n" "$line" "${master[$line]}"
done

answered Aug 24, 2017 at 18:45

glenn jackman

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