How to Append Output and Error in Linux

Learn how to Append Output and Error in Linux using the tee command. This is a useful technique for logging and debugging your scripts and applications.

1. Run the following find command, saving standard output to a file> View the contents of the newly created file:
   $find /etc -name passwd > /tmp/find.out

$cat /tmp/find.out
2. Run another find command, saving standard output to the same file.
   $find /etc -name network > /tmp/find.out
$cat /tmp/find.out
3. Note the the find command, above, overwrote the original find command output. Now, rerun the two find commands, appending the information. View the results:
   
   $rm /tmp/find.out
$find /etc -name passwd > /tmp/find.out
$find /etc -name group >> /tmp/find.out
$cat /tmp/find.out
4. Let’s repeat that command series, but this time, let’s throw away the error messages:
   $rm /tmp/find.out
   $find /etc -name passwd > /tmp/find.out 2> /dev/null
   $find /etc -name squid >> /tmp/find.out 2>/dev/null
   $cat /tmp/find.out