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Addtion of two numbers

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# 1  
Old 08-24-2011
Addtion of two numbers
Code:
for i in 1 2 3 4 5
do
  y='expr $i + 1';
  echo $y
done

After running this shell script i want the output to be
Code:
2
3
4
5
6

but the result is coming as
Code:
expr $i + 1
expr $i + 1
expr $i + 1
expr $i + 1
expr $i + 1

where am i doing wrong ? Cant i use expr to add two numbers and store that result into another variable ?
Please help.
Thank You

Moderator's Comments:
Mod Comment Please use code tags, thanks.
Last edited by zaxxon; 08-24-2011 at 04:52 AM.. Reason: code tags
# 2  
Old 08-24-2011
use ` backtick instead of '

---------- Post updated at 01:14 PM ---------- Previous update was at 01:13 PM ----------

Code:
 
y=`expr $i + 1`
or
y=$(expr $i + 1)

This User Gave Thanks to itkamaraj For This Post:
Sambuddha
# 3  
Old 08-24-2011
Use backquote " ` " rather single quote " ' "
Code:
for i in 1 2 3 4 5
do
y=`expr $i + 1`
echo $y
done

This User Gave Thanks to posix For This Post:
Sambuddha
# 4  
Old 08-24-2011
No need to invoike expr via a subshell.
Code:
for i in 1 2 3 4 5
do
   echo $((i + 1))
done

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