tee command reads the standard input and writes it to both the standard output and one or more files.
$ echo "Hello" | tee fileA fileB fileC
+---------+ +-----+ +--------+
| Command +-->| tee +-->| Stdout |
+---------+ +--+--+ +--------+
|
|
| +-------+
+----->| FileA |
| +-------+
|
| +-------+
+----->| FileB |
| +-------+
|
| +-------+
+----->| FileC |
+-------+
|| visible in terminal || visible in file || existing
Syntax || StdOut | StdErr || StdOut | StdErr || file
==========++==========+==========++==========+==========++===========
> || no | yes || yes | no || overwrite
>> || no | yes || yes | no || append
|| | || | ||
2> || yes | no || no | yes || overwrite
2>> || yes | no || no | yes || append
|| | || | ||
&> || no | no || yes | yes || overwrite
&>> || no | no || yes | yes || append
|| | || | ||
| tee || yes | yes || yes | no || overwrite
| tee -a || yes | yes || yes | no || append
|| | || | ||
n.e. (*) || yes | yes || no | yes || overwrite
n.e. (*) || yes | yes || no | yes || append
|| | || | ||
|& tee || yes | yes || yes | yes || overwrite
|& tee -a || yes | yes || yes | yes || append
https://askubuntu.com/questions/420981/how-do-i-save-terminal-output-to-a-file