This is more for personal reference than anything else. I wanted to log the output of different scripts i’d done but every time I wanted to I had to search the net bcause I kept forgetting (must be old age) so thought i’d put all the info in one place.

To redirect standard output to a file

echo "hello world" > test.txt

Display output as well as store into a file
Answer: tee

echo "hello world" | tee test.txt

To append the standard output to a file

echo"hello world" >> test.txt

Append to file and display it out as well

echo"hello world" | tee -a test.txt

standard output(stdout) – Normal print goes to this

standard error(stderr) – Error related messages go to this

Standard output is redirect to log.txt but stderr is print out.

./script > log.txt

What if I want stderr to be redirect and display the stdout?

./script 2> log.txt

I want both stored into the file.

./script 2&> log.txt

At last, I want both display and redirect to a file:

./script 2>&1 | tee log.txt (my favourite)