[SOLVED] Bash redirections

Issue

Could someone please explain the following behavior of bash and if my understanding is correct:

1. echo abcd > abc def

   the echo abcd prints it out to std out stream, but since due to the presence of ">" it is redirected to the file abc How is def stored as a string in the file abc and not as another file containing the string abcd?

2. echo abcd > abc > def

   This results in the string abcd to be stored in the file def and the file abc remains empty. How ?

Thanks.

Solution

In this command:

echo abcd > abc def foo bar

Only argument after > is used for output filename and rest is used for echo. Hence you get:

cat abc
abcd def foo bar

Then in this command:

echo abcd > abc > def > xyz

Only the last filename after > will actually the output content and remaining ones will be empty:

cat xyz
abcd
cat def
cat abc

To store output in multiple output files use tee like this (with suppressed stdout):

date | tee abc def xyz > /dev/null

Then check content:

cat abc
Mon Dec  7 07:34:01 EST 2015
cat def
Mon Dec  7 07:34:01 EST 2015
cat xyz
Mon Dec  7 07:34:01 EST 2015

Answered By - anubhava

Answer Checked By - Marie Seifert (WPSolving Admin)