|TIME(1)||Linux User's Manual||TIME(1)|
Note: some shells (e.g., bash(1)) have a built-in time command that provides similar information on the usage of time and possibly other resources. To access the real command, you may need to specify its pathname (something like /usr/bin/time).
- When in the POSIX locale, use the precise traditional format
"real %f\nuser %f\nsys %f\n"
- (with numbers in seconds) where the number of decimals in the output for %f is unspecified but is sufficient to express the clock tick accuracy, and at least one.
The default format string is:
%Uuser %Ssystem %Eelapsed %PCPU (%Xtext+%Ddata %Mmax)k %Iinputs+%Ooutputs (%Fmajor+%Rminor)pagefaults %Wswaps
When the -p option is given, the (portable) output format is used:
real %e user %U sys %S
- Elapsed real time (in [hours:]minutes:seconds).
- (Not in tcsh(1).) Elapsed real time (in seconds).
- Total number of CPU-seconds that the process spent in kernel mode.
- Total number of CPU-seconds that the process spent in user mode.
- Percentage of the CPU that this job got, computed as (%U + %S) / %E.
- Maximum resident set size of the process during its lifetime, in Kbytes.
- (Not in tcsh(1).) Average resident set size of the process, in Kbytes.
- Average total (data+stack+text) memory use of the process, in Kbytes.
- Average size of the process's unshared data area, in Kbytes.
- (Not in tcsh(1).) Average size of the process's unshared stack space, in Kbytes.
- Average size of the process's shared text space, in Kbytes.
- (Not in tcsh(1).) System's page size, in bytes. This is a per-system constant, but varies between systems.
- Number of major page faults that occurred while the process was running. These are faults where the page has to be read in from disk.
- Number of minor, or recoverable, page faults. These are faults for pages that are not valid but which have not yet been claimed by other virtual pages. Thus the data in the page is still valid but the system tables must be updated.
- Number of times the process was swapped out of main memory.
- Number of times the process was context-switched involuntarily (because the time slice expired).
- Number of waits: times that the program was context-switched voluntarily, for instance while waiting for an I/O operation to complete.
- Number of filesystem inputs by the process.
- Number of filesystem outputs by the process.
- Number of socket messages received by the process.
- Number of socket messages sent by the process.
- Number of signals delivered to the process.
- (Not in tcsh(1).) Name and command-line arguments of the command being timed.
- (Not in tcsh(1).) Exit status of the command.
- -f format, --format=format
- Specify output format, possibly overriding the format specified in the environment variable TIME.
- -p, --portability
- Use the portable output format.
- -o file, --output=file
- Do not send the results to stderr, but overwrite the specified file.
- -a, --append
- (Used together with -o.) Do not overwrite but append.
- -v, --verbose
- Give very verbose output about all the program knows about.
- -q, --quiet
- Don't report abnormal program termination (where command is terminated by a signal) or nonzero exit status.
- Print a usage message on standard output and exit successfully.
- -V, --version
- Print version information on standard output, then exit successfully.
- Terminate option list.
GNU time version 1.7 is not yet localized. Thus, it does not implement the POSIX requirements.
The environment variable TIME was badly chosen. It is not unusual for systems like autoconf(1) or make(1) to use environment variables with the name of a utility to override the utility to be used. Uses like MORE or TIME for options to programs (instead of program pathnames) tend to lead to difficulties.
It seems unfortunate that -o overwrites instead of appends. (That is, the -a option should be the default.)
Mail suggestions and bug reports for GNU time to firstname.lastname@example.org. Please include the version of time, which you can get by running
and the operating system and C compiler you used.