Unix or Linux tee command is similar to ‘cat’ command with only one difference. It reads the input and writes in in a file also outputs in the terminal.
Sample syntax with tee command :
$ cat <filename> | tee<new file>
Like example of
tee command :
$ cat weeks.txt | tee new_file.txt
See your terminal after run the command, file
new_file.txt is create with the help of tee command. And the contents of the
new_file.txt is same as the
weeks.txt. Also the contents of
weeks.txt is shown in terminal.
Lets see a live example
In this example, we transferred the output of first command to a file. Firstly, we’re in a directory
/var/log. This is the directory of ubuntu file systems to store logs. There is a file named
dmesg, which stores the system logs.
wc -l dmesg, outputs the line count of the file. When we pipe the command to tee
/tmp/test.txt, the output of the
wc -l dmesg command gets written to the file
/tmp/test.txt, and also gets printed in the terminal.
Use tee -a if you want to append to the file
If you want the output to append to the file instead of replacing the contents of the file use