Linux pipeline and redirection

Redirect output

$ls -l > lsoutput.txt This command saves the output of the ls command to the file lsoutput.txt.

$ps >> lsoutput.txt Use the >> operator to append the output to a file. This command appends the output of the ps command to the end of the specified file.

If you want to redirect the standard error output, you need to add the file descriptor number to be redirected before the > operator. Since the standard error output has a file descriptor number of 2, we use the 2> operator. This method is useful when you need to discard the error message and prevent it from appearing on the screen.

The following command redirects standard output and standard error output to different files: $kill -HUP 1234 >killout.txt 2>killerr.txt

If you want to Both sets of output are redirected to a file, and the >& operator can be used to combine the two outputs. As shown below: $kill -l 1234 >killouterr.txt 2>&1

Pipeline

Usually the output of one process is piped to the input of another process.

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