time Command

Purpose

Prints the time of the execution of a command.

Syntax

time [ -p ] Command [ Argument ... ]

Description

The time command prints the elapsed time during the execution of a command, time in the system, and execution time of the time command in seconds to standard error.

Note: Sleep time is not charged to either system or user time.

The time command is also built into the C shell (csh) and Korn shell (ksh) with a different format. To run the time command while in the csh and ksh shells, enter:

/usr/bin/time

Flags

Item	Description
-p	Writes the timing output to standard error. Seconds are expressed as a floating-point number with at least one digit following the radix character. The standard format for this flag is as follows: `"real %f\nuser %f\nsys %f\n", <real seconds>, <user seconds>, <system seconds>`

Exit Status

If you use the Command parameter, the exit status of the time command is the exit status of the specified command. Otherwise, the time command exits with one of the following values:

Item	Description
1-125	Indicates an error occurred in the time command.
126	Indicates the command specified by the Command parameter was found but could not be invoked.
127	Indicates the command specified by the Command parameter could not be found.

Examples

To measure the time required to run a program, enter:
```
/usr/bin/time -p a.out
```
This command runs the program a.out and writes the amount of real, user, and system time to standard error, in the format specified by the -p flag; for example:
```
real      10.5
user      0.3
sys       3.6
```
To save a record of the time command information in a file, enter:
```
/usr/bin/time a.out 2> a.time
```

Files

Item	Description
/usr/bin/time	Specifies the path of the time command.