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Use variable in bash

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# 1  
Old 11-08-2013
Use variable in bash
Code:
$ p="1 2 5 8"
$ set -- $p
$ echo $3
5
$ k=3
$ echo \$${k}
$3

I want the "echo \$${k}" to get the output 5 , how to modify ?
# 2  
Old 11-08-2013
Code:
echo $(eval echo \$${k})

(although using eval is generally frowned upon as it can introduce security holes)
This User Gave Thanks to CarloM For This Post:
yanglei_fage
# 3  
Old 11-08-2013
Check this link.
Last edited by balajesuri; 11-08-2013 at 05:42 AM.. Reason: I was a tad slower than CarloM! Blame it on Friday.. ha ha ha! :-D
# 4  
Old 11-08-2013
Quote:
Originally Posted by CarloM
Code:
echo $(eval echo \$${k})

(although using eval is generally frowned upon as it can introduce security holes)
can you explain ?
# 5  
Old 11-08-2013
Quote:
Originally Posted by yanglei_fage
can you explain ?
balajesuri's link gives a better way (and an explanation of why eval can be bad).
# 6  
Old 11-08-2013
You could also use eval echo \$$k with all the known caveats on eval.
# 7  
Old 11-11-2013
Could use put the values into an array and address is that way?

Code:
#!/bin/ksh

set -A p 1 2 5 8
k=2
echo "${p[$k]}"

Note that the array counter is 2 to get the output 5.

I don't see an operating system named or a shell, so you might have to adjust this if you want anything other than ksh



I hope that this helps.


Robin
Liverpool/Blackburn
UK
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