I want to execute a unix time command using perl, and capture the output (specifically, the time it takes the command to execute).
i tried using the system command:
system("time command ");
however, when i try to capture the output, the capture output does not contain the amount of time it took to execute
when i try to do:
$var = `time command `;
there is the same problem (the ouput from the command is saved in the variable; however, the time is not)
So, how do i capture the time it takes a unix command to execute?
10  17662 
Your script is doing exactly what you designed it to do. It is storing the output of the command you issued in the variable you specified. Even on the command line the command won't tell you how long it took to execute. It sounds like you want to do some sort of benchmarking of Perl while executing system commands. Unfortunately, I don't have any experience with benchmarking and couldn't be much help.
Regards,
Jeff
when i type in "time command " at the command line i get the following:
...
lines of output
....
real 0.5
user 0.4
sys 0.0
I want to store ALL the above output in a file (using a perl script). When i try to do this, i am only able to store the "lines of ouput" part. I am unable to store those last three lines, and i cant figure out why I am unable to.
Ok, have you tried this"
@var = `time command`;
That should take each line and put it into its own element. So, element [0] would be "lines of output"
Regards,
Jeff
I want to execute a unix time command using perl, and capture the output (specifically, the time it takes the command to execute).
i tried using the system command:
system("time command ");
however, when i try to capture the output, the capture output does not contain the amount of time it took to execute
when i try to do:
$var = `time command `;
there is the same problem (the ouput from the command is saved in the variable; however, the time is not)
So, how do i capture the time it takes a unix command to execute?
I have no experience with the time command in unix. Whenever I need benchmarking, I would simply roll my own using Time::HiRes and the gettimeofday function.
However, throwing together a quick script, this is what I obtained. -
#! /usr/bin/perl
-
# scratch.pl
-
-
print "Hello world\n";
-
sleep 2;
-
print "Goodbye World\n";
-
-
#! /usr/bin/perl
-
# scratch2.pl
-
-
my $x = `time -p perl scratch.pl`;
-
print $x;
-
And the output of running scratch2.pl -
$ perl scratch2.pl
-
real 2.00
-
user 0.00
-
sys 0.00
-
Hello world
-
Goodbye World
-
Seems to work ok to me.
- Miller
Comment out line 5 of scratch2.pl and run the program. The output is:
real 2.00
user 0.00
sys 0.00
Alternatively, add the line - print $x; - to scratch2.pl and run the program (now we are printing $x twice). The output is:
real 2.00
user 0.00
sys 0.00
Hello world
Goodbye World
Hello world
Goodbye World
In other words, the timing information was never captured in the variable $x !
I believe the "time" command in unix prints to standard error rather than standard out, which may be why you aren't capturing it. See discussion of capturing standard error at: http://stein.cshl.org/genome_informatics/unix2/index.html#stderr
Note: you can also do some shell scripting, and try something like:
( time <command> ) | perl -options '....'
Depending on your shell, I suppose. But this syntax works on at least come tcsh (and csh?) varieties.
I believe the "time" command in unix prints to standard error rather than standard out, which may be why you aren't capturing it. See discussion of capturing standard error at: http://stein.cshl.org/genome_informatics/unix2/index.html#stderr
If that is the case, then all he would have to do is add a 2>&1 to the end of his command and it will send the error to wherever he specified the standard out to go to.
Regards,
Jeff
On Solaris 10 (using bash shell), I had trouble getting `time -p <command> 2>&1` to work. I solved it by executing the time command in its own shell as follows:
TIMING=`bash -c "time ls -l" 2>&1`
Sign in to post your reply or Sign up for a free account.
Similar topics
by: Hugh Macdonald |
last post by:
I'm calling a command from within a python script and I need to be
able to both catch the output (stdout and stderr) from it and also
have the PID (so that I can kill it)
I can do one or other...
|
by: rkoida |
last post by:
Hello evryone
I am a newbie to python. I have a makefile which i can compile in
UNIX/LINUX, But i
I am planning to write a python script which actually does what my
MAKEFILE does. The make file...
|
by: Glen |
last post by:
Hi,
I just have a quick question
Im trying to initialize a string (or char) variable with the information
created by the output of a shell (or DOS) command..
Example:
I want to execute a...
|
by: francescomoi |
last post by:
I'm trying to show current Unix time in C.
Is it possible?
|
by: Kevin Mansel via .NET 247 |
last post by:
Ok, basically this is my problem. I'm building a console app tocall a dos program. So i'm using the Shell command to call theprogram, now depending on what happens, I want to read theoutput that...
|
by: Luis P. Mendes |
last post by:
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
Hi,
I've inserted a couple hundred rows in a table in Postgres via psycopg2.
The first field of each row is a certain unix time (since epoch)...
|
by: Peter A. Schott |
last post by:
Not sure what I should do here. I know that DOS/CMD can capture the output of
EXE files in Win32. I know that os.popen() has been recommended for this, but
the couple of times I've tried, it...
|
by: David T. Ashley |
last post by:
I have Red Hat Enterprise Linux 4.
I was just reading up about UTC and leap seconds.
Is it true on my system that the Unix time may skip up or down by one second
at midnight when there is a...
|
by: niskin |
last post by:
I am running a system command and I need to capture the output so that, if the command has done what it is meant to, the program does something different. If I do this:
int i;
i=system("cd...
|
by: Charles Arthur |
last post by:
How do i turn on java script on a villaon, callus and itel keypad mobile phone
|
by: BarryA |
last post by:
What are the essential steps and strategies outlined in the Data Structures and Algorithms (DSA) roadmap for aspiring data scientists? How can individuals effectively utilize this roadmap to progress...
|
by: nemocccc |
last post by:
hello, everyone, I want to develop a software for my android phone for daily needs, any suggestions?
|
by: Hystou |
last post by:
There are some requirements for setting up RAID:
1. The motherboard and BIOS support RAID configuration.
2. The motherboard has 2 or more available SATA protocol SSD/HDD slots (including MSATA, M.2...
|
by: marktang |
last post by:
ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However,...
|
by: Hystou |
last post by:
Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can...
|
by: Hystou |
last post by:
Overview:
Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows...
|
by: agi2029 |
last post by:
Let's talk about the concept of autonomous AI software engineers and no-code agents. These AIs are designed to manage the entire lifecycle of a software development project—planning, coding, testing,...
|
by: isladogs |
last post by:
The next Access Europe User Group meeting will be on Wednesday 1 May 2024 starting at 18:00 UK time (6PM UTC+1) and finishing by 19:30 (7.30PM).
In this session, we are pleased to welcome a new...
| |
