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The time(1) command allows you to time any command, by passing it as arguments to time.

I know it's possible to redirect stderr and stdout to a file via 2>&1, and there's also tee(1) which allows one to copy its input to both the screen and a file. However, I do not know how to add timestamps to logs.

Is there a tool to redirect stderr and stdout to a file, AND append timestamps to it for logging purposes?

Satō Katsura
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Edward
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    I read your first sentence multiple times, but it doesn't make any sense. Did you forget 'to' between 'you' and 'time'? Any reason to fumble with adding time **after** the entry in a log? Why are you not using `logger` and get a standard entry (with timestamp **before** the log entry)? – Anthon Dec 17 '16 at 08:18

2 Answers2

5

You could use ts(1) from moreutils.

ts from moreutils will prepend a timestamp to every line of input you give it. You can format it using strftime too.

$ echo 'foo bar baz' | ts
Mar 21 18:07:28 foo bar baz
$ echo 'blah blah blah' | ts '%F %T'
2012-03-21 18:07:30 blah blah blah
$

To install it:

sudo apt-get install moreutils

Contents copied from this answer: https://stackoverflow.com/a/9813614/221689

Community
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Charley
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Try annotate-output from Debian's devscripts package. It shows timestamps, and writes "O" before standard output, and "E" before standard error. Example:

# run `ls` on one file that exists, and one that doesn't...
annotate-output ls /bin/bash /tmp/boosh

Output:

03:30:52 I: Started ls /bin/bash /tmp/boosh
03:30:52 O: /bin/bash
03:30:52 E: ls: cannot access '/tmp/boosh': No such file or directory
03:30:52 I: Finished with exitcode 2
agc
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  • Interesting. This does not have date stamp, am I right? – Edward Dec 17 '16 at 09:00
  • @Edward, it *does* have date stamping, just pass it a `date` string: `annotate-output +"%D %H:%M:%S" ls /bin/bash /tmp/boosh`; see `man date` for a list of all the date string format codes. – agc Dec 17 '16 at 17:14