Performance of let and expr


 
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# 1  
Old 01-11-2012
Performance of let and expr

i have been told that 'let' is faster than 'expr' in terms of performance.
Is this correct? if yes, why is it so?
i am not able to see any performance difference in small arithmetic operations.

Thanks
# 2  
Old 01-11-2012
Both "let" and "expr" have many uses.
Please give real examples or your work and show us how you are measuring the figures.

Please tell us precisely what Operating System and version you have and what Shell you are using.

Btw. Many posters would not use either "let" or "expr" for arithmetic.
# 3  
Old 01-11-2012
I am asking in general.
Will there be any performance impact between these 2 commands?
Code:
c=`expr $a + $b`
let c=$a+$b

My operating system is ubuntu 11.30 and i am using bash shell.

Thanks
# 4  
Old 01-11-2012
expr is an external utility, not a shell builtin -- which is why you call it in backticks instead of just assigning. Its performance cost is therefore quite high -- you must load, run, and wait for it to quit every time you use it.

It's compatible with all shells, however.

In BASH and KSH you can also do things like A=$((B+C+9))
 
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