tee command is normally used to split the output of a program so that it can be both displayed and saved in a file.” wikipedia
This command create a file.txt and anything you type is : displayed on the screen AND written to the file.
ctrl + z or ctrl + c
Use this command above to end the session
tee -a file.txt
Same thing as the previous command, except this time it is using the -a (append) flag.
“Note: When tee is used with a pipe, the output of the previous command is written to a temporary file. When that command finishes, tee reads the temporary file, displays the output, and writes it to the file(s) given as command-line argument.” wikipedia
echo "We are YCSoftware" | tee -a file.txt
The output of the echo command to be written to the file file.txt AND also displayed it on the screen