This command pipeline sorts the output of the "ps -ef" command. Because no arguments are supplied to the sort command, the output is sorted in alphabetic order by the first column of the ps -ef output (i.e., the output is sorted alphabetically by username).

ls -al | sort +4n

This command performs a numeric sort on the fifth column of the "ls -al" output. This results in a file listing where the files are listed in ascending order, from smallest in size to largest in size.

ls -al | sort +4n | more

The same command as the previous, except the output is piped into the more command. This is useful when the output will not all fit on one screen.

ls -al | sort +4nr

This command reverses the order of the numeric sort, so files are listed in descending order of size, with the largest file listed first, and the smallest file listed last.