How to redirect standard output to multiple log files? The following does not work:

some_command 1> output_log_1 output_log_2 2>&1
  • 5
    With zsh, you can use some_command >output_log_1 >output_log_2. – jofel Jun 21 '12 at 8:36

See man tee:

NAME: tee - read from standard input and write to standard output and files

SYNOPSIS: tee [OPTION]... [FILE]...

Accordingly:

echo test | tee file1 file2 file3
  • can the stderr be also redirected in more than one file? – fromnaboo Jun 23 '12 at 9:07
  • Yes, it can be done by virtue of redirection: find / -name test 2>&1 | tee file1 file2 file3 – akond Jun 23 '12 at 18:27
  • @akond, cmd 2>&1 | tee log1 log2 I tried executing like above, but i need to press ctrl-c to redirect it to second log file. also the output is printed on the console. I want command output to be redirected to logs but not on the console. any help is appreciated. – doubledecker Jun 25 '12 at 10:34
  • @doubledecker The tee command writes stdin to file(s) and also to stdout. If you don't want the output to appear on the terminal, you have to redirect to /dev/null like you normally would. – Minix Dec 16 '14 at 8:28
  • 2
    It is also possible to append to multiple files: echo test | tee --append file1 file2 – user1364368 Jul 29 '16 at 17:53

Let's say your output is generated from a function, cmd() :

cmd() {
    echo hello world!
}

To redirect the output from cmd to two files, but not to the console, you can use:

cmd | tee file1 file2 >/dev/null

This will work for multiple files, given any data source piping to tee:

echo "foobarbaz" | tee file1 file2 file3 file4 > /dev/null

This will also work:

echo $(cmd) | tee file1 file2 >/dev/null

Without the /dev/null redirection, tee will send output to stdout in addition to the files specified.

For example, if this is run from the console, you'll see the output there. Run from a crontab, the output will appear the status message which is mailed to you (also see Gilles' answer here https://unix.stackexchange.com/a/100833/3998).

This worked for me in bash on Ubuntu 12.04, and has been verified in Ubuntu 14.04 using GNU bash 4.3.11(1), so it should work on any recent GNU bash version.

  • @doubledecker -- this looks like it satisfies your conditions, so can be accepted as the answer. Also, +1 as I've tested this under GNU bash (version 4.3.11(1)-release (i686-pc-linux-gnu)) in Ubuntu 14.04. – belacqua Jun 20 '14 at 19:47

It's an old post but I just found it now...

Instead of redirecting the output to > /dev/null you can redirect it to the last file:

echo "foobarbaz" | tee file1 > file2

Or for appending the output:

echo "foobarbaz" | tee -a file1 >> file2
  • this is more or less what other answer said (except for -a in tee) – Archemar Apr 29 '16 at 9:19
  • This is the way to go. – 71GA Nov 12 '17 at 18:44

As @jofel mentioned in a comment under the answer, this can be done natively in zsh:

echo foobar >file1 >file2 >file3

or, with brace expansion:

echo foobar >file{1..3}

Internally this works very similarly to the tee answers provided above. The shell connects the command's stdout to a process that pipes to multiple files; therefore, there isn't any compelling technical advantage to doing it this way (but it does look real good). See the zsh manual for more.

Unable to comment, however, another way to express

echo "foobarbaz" | tee file1 file2 file3 file4 file5 file6 file7 file8 > /dev/null

Could be simplified to this, when dealing with many files.

echo "foobarbaz" | tee file{1..8} > /dev/null
  • 2
    How is this really different from the other answers already given? Especially since few people likely want literal file1 through file8 as their names and those are likely just example placeholders for the names of the files – Eric Renouf Dec 28 '15 at 14:56
  • 1
    Likely or not, this is exactly the solution I needed, and thought it could help someone else. – user149146 Dec 28 '15 at 19:32

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