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Shell Programming and Scripting

dynamic variable name

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# 1  
Old 07-28-2010
dynamic variable name
I found one post in another site with a solution for my problem
the below solution should explain what I want.

Code:
 
#!/bin/sh
 
first="one"
second="two"
third="three"
 
myvar="first"
echo ${!myvar}

But this gives error 'bad substitution'

System info
SunOS sundev2 5.9 Generic_Virtual sun4u sparc SUNW,Sun-Fire-V245

Any help?
# 2  
Old 07-28-2010
What output do you want from this line? Not possile to guess because it gives a syntax error.

Quote:
echo ${!myvar}
# 3  
Old 07-28-2010
the output should be
Code:
one

Ok this works in bash
Code:
#!/bin/bash

cell1="one"
cell2="two"
cell3="three"

i=1

while [ $i -lt 4 ]
do
    var_name="cell"$i
    echo ${!var_name}
    i=`expr $i + 1`
done

output
Code:
one
two
three

is it possible in sh
Last edited by johnbach; 07-28-2010 at 12:45 PM..
# 4  
Old 07-28-2010
Second attempt. This time with the eval syntax correct. Tried with Bourne Shell, ksh and Posix Shell.

Code:
#!/bin/sh

cell1="one"
cell2="two"
cell3="three"

i=1

while [ $i -lt 4 ]
do
    var_name="cell${i}"
    eval echo \$${var_name}
    i=`expr $i + 1`
done

one
two
three

Last edited by methyl; 07-28-2010 at 01:07 PM..
This User Gave Thanks to methyl For This Post:
johnbach
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