Grep Time Command Output

Grep time command output

time writes its output to stderr, so you need to pipe stderr instead of stdout. But it's also important to remember that time is part of the syntax of bash, and it times an entire pipeline. Consequently, you need to wrap the pipeline in braces, or run it in a subshell:

 $ { time ls -l >/dev/null; } 2>&1 | grep real
 real   0m0.005s

With Bash v4.0 (probably universal on Linux distributions but still not standard on Mac OS X), you can use |& to pipe both stdout and stderr:

{ time ls -l >/dev/null; } |& grep real

Alternatively, you can use the time utility, which allows control of the output format. On my system, that utility is found in /usr/bin/time:

/usr/bin/time -f%e ls -l >/dev/null 

man time for more details on the time utility.

How to grep the file with time range

awk '$0>="2018-07-11 10" && $0<="2018-07-11 11" && /Connection Refused/' file

Output:

2018-07-11 10:15:06,288 - User logged in Connection Refused
2018-07-11 10:18:06,288 - User logged in Connection Refused

grep the time duration from ping output

Use the PCRE mode on GNU grep by enabling the -P flag on, to extract the milli-seconds values alone

ping -4 www.google.com | grep -oP ".*time=\K\d+" 

where the \K escape sequence stands for

\K: This sequence resets the starting point of the reported match. Any previously matched characters are not included in the final matched sequence.

Or you could do away with any GNU-ism tools needed and just use a POSIX sed to do

ping -4 www.google.com | sed -n 's/.*time=\([[:digit:]]*\).*/\1/p'

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