UNIX Command Line

As you know the 'time' command run programs and summarize system resource usage. Here is a way how you can redirect 'time' command output to file. I would recomend you to go through this page to understand more about 'time' command.

e.g. We are executing 'prog.sh' along with 'time' command.

$ time ./prog.sh 
Initiating merge
Merge completed

real	0m8.803s
user	0m0.010s
sys	0m0.000s

#Trying to redirect the output to a file

$ time ./prog.sh > out.txt

real	0m8.804s
user	0m0.020s
sys	0m0.000s

#out.txt content:

$ cat out.txt 
Initiating merge
Merge completed

#So it only redirected the STDOUT of the script executed, but the 'time' command outut is not redirected.
#This is becuase the command time sends it's output to STDERR (instead of STDOUT)
#To capture output of 'time' command:

$ { time ./prog.sh ; } 2> out.txt
Initiating merge
Merge completed

#Now out.txt content:

$ cat out.txt 

real	0m8.303s
user	0m0.010s
sys	0m0.000s

#And to capture output of script as well as time command:

$ { time ./prog.sh ; } &> out.txt

#'out.txt' now has both the outputs.

$ cat out.txt 
Initiating merge
Merge completed

real	0m8.303s
user	0m0.020s
sys	0m0.000s

As I have mentioned in my earlier post on UNIX 'time' command, there's two types of time command available:
1) Shell's in-build time: Gives only scheduler information
2) /usr/bin/time: Gives more information, also allows formatting the output

The second (/usr/bin/time) one accepts output redirection without code block:

$ /usr/bin/time ./prog.sh &> newout.txt

$ cat newout.txt 
Initiating merge
Merge completed
0.00user 0.01system 0:08.30elapsed 0%CPU (0avgtext+0avgdata 5728maxresident)k
0inputs+8outputs (0major+719minor)pagefaults 0swaps

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