Performance profiling tools for shell scripts

I'm attempting to speed up a collection of scripts that invoke subshells and do all sorts of things. I was wonder if there are any tools available to time the execution of a shell script and its nested shells and report on which parts of the script are the most expensive.

For example, if I had a script like the following.


echo "hello"
echo $(date)
echo "goodbye"

I would like to know how long each of the three lines took. time will only only give me total time for the script. bash -x is interesting but does not include timestamps or other timing information.


You can set PS4 to show the time and line number. Doing this doesn't require installing any utilities and works without redirecting stderr to stdout.

For this script:

#!/bin/bash -x
# Note the -x flag above, it is required for this to work
PS4='$(date "+%s.%N ($LINENO) + ")'
for i in {0..2}
    echo $i
sleep 1
echo done

The output looks like:

+ PS4='$(date "+%s.%N ($LINENO) + ")'
1291311776.108610290 (3) + for i in '{0..2}'
1291311776.120680354 (5) + echo 0
1291311776.133917546 (3) + for i in '{0..2}'
1291311776.146386339 (5) + echo 1
1291311776.158646585 (3) + for i in '{0..2}'
1291311776.171003138 (5) + echo 2
1291311776.183450114 (7) + sleep 1
1291311777.203053652 (8) + echo done

This assumes GNU date, but you can change the output specification to anything you like or whatever matches the version of date that you use.

Note: If you have an existing script that you want to do this with without modifying it, you can do this:

PS4='$(date "+%s.%N ($LINENO) + ")' bash -x scriptname

Need Your Help

Twitter authorized / signed get request returing 401 not authorized

c# oauth httpwebrequest twitter

I'm trying to make an authorized get request to It keeps returning 401 not authorized. .Ive checked the header and base string against the ones generated in the...

About UNIX Resources Network

Original, collect and organize Developers related documents, information and materials, contains jQuery, Html, CSS, MySQL, .NET, ASP.NET, SQL, objective-c, iPhone, Ruby on Rails, C, SQL Server, Ruby, Arrays, Regex, ASP.NET MVC, WPF, XML, Ajax, DataBase, and so on.