time command

[ppanula]

Under CentOS i get error message "-f: command not found" when i try to run benchmarks.

Not sure but if i modify benchmark script from just time to /usr/bin/time all works. Is time some sort of shell's inside command?

Would it be better to modify all benchmark scripts to use time with full path?

[Michael]

Hmmm I had just modified all the scripts the other day from /usr/bin/time to time. That must have been why I had done it that way in the first place, I'll change it back. Sorry about that.

[Kano]

time is a builtin when you use bash as sh.

[deanjo]

Yes, according to tldp.org

"As of version 2.0 of Bash, time became a shell reserved word, with slightly altered behavior in a pipeline."

There is also the times command that gives statistics on the system time elapsed when executing commands.

[uncle_fungus]

That can't always be the case, since I'm using Bash 3.1

[uncle_fungus@Iguana phoronix-test-suite]$ bash --version
GNU bash, version 3.1.17(1)-release (i586-mandriva-linux-gnu)
Copyright (C) 2005 Free Software Foundation, Inc.

And time in a bash script uses /usr/bin/time

[deanjo]

That can't always be the case, since I'm using Bash 3.1

[uncle_fungus@Iguana phoronix-test-suite]$ bash --version
GNU bash, version 3.1.17(1)-release (i586-mandriva-linux-gnu)
Copyright (C) 2005 Free Software Foundation, Inc.

And time in a bash script uses /usr/bin/time

Maybe it's because we are using a newer version of bash.

dean@linux:~> bash --version
GNU bash, version 3.2.39(1)-release (x86_64-suse-linux-gnu)
Copyright (C) 2007 Free Software Foundation, Inc.

[Kano]

Check this:

$ bash -c time

real 0m0.000s
user 0m0.000s
sys 0m0.000s
$ bash -c /usr/bin/time
Usage: /usr/bin/time [-apvV] [-f format] [-o file] [--append] [--verbose]
[--portability] [--format=format] [--output=file] [--version]
[--quiet] [--help] command [arg...]

Also check

readlink /bin/sh

[deanjo]

Check this:

$ bash -c time

real 0m0.000s
user 0m0.000s
sys 0m0.000s
$ bash -c /usr/bin/time
Usage: /usr/bin/time [-apvV] [-f format] [-o file] [--append] [--verbose]
[--portability] [--format=format] [--output=file] [--version]
[--quiet] [--help] command [arg...]

Also check

readlink /bin/sh

dean@linux:~> bash -c time

real    0m0.000s
user    0m0.000s
sys     0m0.000s
dean@linux:~> bash -c /usr/bin/time
Usage: /usr/bin/time [-apvV] [-f format] [-o file] [--append] [--verbose]
       [--portability] [--format=format] [--output=file] [--version]
       [--help] command [arg...]
dean@linux:~> readlink /bin/sh
bash
dean@linux:~>

[Kano]

And thats the standard behaviour if you have /bin/sh as bash to use the bash time builtin. When you write #!/bin/sh scripts with time and you set sh to dash then the external time is used.

[uncle_fungus]

It appears my bash isn't behaving as "standard" then.

[uncle_fungus@Iguana phoronix-test-suite]$ bash -c time
Usage: time [-apvV] [-f format] [-o file] [--append] [--verbose]
       [--portability] [--format=format] [--output=file] [--version]
       [--quiet] [--help] command [arg...]
[uncle_fungus@Iguana phoronix-test-suite]$ bash -c /usr/bin/time
Usage: /usr/bin/time [-apvV] [-f format] [-o file] [--append] [--verbose]
       [--portability] [--format=format] [--output=file] [--version]
       [--quiet] [--help] command [arg...]
[uncle_fungus@Iguana phoronix-test-suite]$ readlink /bin/sh
bash