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Identify variables used in the shell script

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# 1  
Old 03-28-2013
Identify variables used in the shell script
Hi,

Is there any simple way to get/identify the variables that are used in a file and print those variable names. If I have something like this in a file,

Code:
 
/$var/temp_dir/${var2}${var3}.log

I want to display the variables 'var', 'var2' and 'var3' from that file. I tried something like this,

Code:
$ echo '/$var/temp_dir/${var2}${var3}.log' | grep -v '\$\$' | sed -e 's/\$/\n\$/g' | sed -e 's/\/*//g' -e 's/\..*//g'

$var
${var2}
${var3}

It seems to be working.. but I dont think it works in all cases.

I think that we can apply a logic that identifies everything after $ sign is considered as variable name until it finds out a character that cant be a part of variable. But not sure how to implement it.

Can any one please help me?

Thanks in advance.

---------- Post updated at 06:49 PM ---------- Previous update was at 04:03 AM ----------

Anyone, please help me...
# 2  
Old 03-28-2013
Shell Command Language may be helpful, as it defines the actual format of variables (parameters).
# 3  
Old 03-28-2013
Does your shell supports grep -o ??
# 4  
Old 03-28-2013
Nope.. I am Redhat Linux and it doesn't have that
Code:
grep -o

option..
# 5  
Old 03-28-2013
Try

Code:
$ echo '/\$var/temp_dir/\${var2}\${var3}.log'  | sed -n 's/.*\(\$[a-zA-Z0-9]*\).*/\1/'

This should give you $var.

I am trying to extract others as well.
# 6  
Old 03-28-2013
Missed p? Seems to be matching too much as well (AIX):
Code:
[user@host]  echo '/\$var/temp_dir/\${var2}\${var3}.log'  | sed -n 's/.*\(\$[a-zA-Z0-9]*\).*/\1/'
[user@host]  echo '/\$var/temp_dir/\${var2}\${var3}.log'  | sed -n 's/.*\(\$[a-zA-Z0-9]*\).*/\1/p'
$

You could have something along the lines of:
Code:
 echo '/$var/temp_dir/${var2}$var3.log'  | sed -n 's/[^$]*\($[[:alnum:]]*\)[^[:alnum:]].*/\1/p'
$var

but it will only handle 1 variable per line, and probably doesn't deal correctly with shell builtins...
# 7  
Old 03-28-2013
I did this

Code:
echo "/\$var/temp_dir/\${var2}\${var3}.log" | tr '\/' '\n' | sed -n 's/.*\([\$][{]*[A-Za-z0-9]*[}]*\).*/\1/p'

I got $var and ${var3} as output! Smilie

Little tuning up of regex should do Smilie
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