Bash | Measure the execution time

Measure the execution time

`time`

The time that you are using is the bash shell built in time which the only option is -p

The command "time" report a execution time information

time sleep 1

Output:
real 0m1.001s
user 0m0.000s
sys 0m0.001s

Description:

Real - time from start to finish.
User - the amount of CPU time spent in use-mode. It is actual CPU time used in executing the process.
Sys - the amount of CPU time spent in kernel.

`date +%s`

You can measure execution time by subtraction start date and end date:

# time elapsed
start_time="$(date -u +%s)"

commands...

echo "====================="
end_time="$(date -u +%s)"
elapsed="$(($end_time-$start_time))"
echo "Total of $elapsed seconds elapsed for process"
time_mins="$(($elapsed /60))"
echo "Total of $time_mins minutes elapsed for process"
time_hours="$(($elapsed /60/60))"
echo "Total of $time_hours hours elapsed for process" 
echo "====================="

`> log 2>&1 &`

1	`$ time ./Allrun > output_file.txt 2>&1 &`

`tee`

It basically breaks the output of a program so that it can be both displayed and saved in a file. It does both the tasks simultaneously, copies the result into the specified files or variables and also display the result.