Bash counting executed time

Question

I want to write a script in bash that will save to file how long it have been executed

I want output to look like this: 1 minute 2 minute ...

Answer 1

Requirements

You need to install time (not the shell built-in).

To validate that you have the right one: $ which time

This is the expected output:

$ which time
/usr/bin/time

Solution

Assuming that you have a function called main, in which your main scripting code is included

function main() {
  echo "Sleeping .."
  sleep(5)
  echo "This is the first arg: ${1}"
  echo "This is the second arg: ${2}"
}

To time this function call, do as follows (arguments for reference):

main "HELLO" "WORLD" | $(which time) -o "OUTPUT_FILENAME_FOR_TIME" -f "%e" $(which bash)

Explanation

We are piping /usr/bin/time to the function call to time it. We are calling time using $(which time) because we do not want the shell built-in. After that we are passing the -o argument to define our output file and then the -f argument is used to define the time format. In my example, I used seconds. In the end, we pass which shell we are using, and in our case we are using bash, so $(which bash).

man time to read about other formats and of course the proper usage of the program

I always use seconds because it is easier to convert them to anything.

EDIT #1

You can use the GNU tool command instead of using the absolute path of time

 $ command time

instead of

 $ $(which time)