LPI 101-500 - LPIC-1 Exam 101, Part 1 of 2, version 5.0

The :e command in vi is used to edit a file. If the file name is not specified, it will edit the current file. If the file has been changed by another process, the :e command will reload the file with the new content, discarding any unsaved changes made in vi. Therefore, the :e command can be used to reopen the file for editing with the new content without exiting vi. The other options are either invalid or do not perform the desired task. The :r command is used to read the content of another file or command and insert it into the current file. The :n command is used to edit the next file in the argument list, if any. The :w command is used to write the current file to disk, optionally with a new name. References:

LPIC-1 Exam 101 Objectives, Topic 103: GNU and Unix Commands, 103.7 Use and edit text files

LPIC-1 Linux Administrator 101-500 Exam FAQ, LPIC-1 Exam 101 Objectives, GNU and Unix Commands (Total Weight: 25)

In Bash, inserting 1>&2 after a command redirects standard output to standard error. This means that the output of the command that normally goes to the standard output stream (file descriptor 1) will be sent to the standard error stream (file descriptor 2) instead. This can be useful if we want to capture or discard both the normal output and the error output of a command. For example, if we want to run a command and send both its output and error to /dev/null (a special device that discards any data written to it), we can use:

command > /dev/null 1>&2

This will redirect the standard output of command to /dev/null, and then redirect the standard error of command to the same place as the standard output, which is /dev/null. The other options are not correct because:

A. standard error to standard input: This is not possible, because standard input is a read-only stream, and we cannot redirect output to it.

B. standard input to standard error: This is not what 1>&2 does, because 1 refers to standard output, not standard input. To redirect standard input to standard error, we would need to use 0>&2, where 0 refers to standard input.

D. standard error to standard output: This is not what 1>&2 does, because it would require the opposite order of file descriptors: 2>&1. This would redirect standard error to standard output, not the other way around.

E. standard output to standard input: This is not possible, for the same reason as option A. References:

Bash redirections cheat sheet

How to redirect stderr to a file - Linuxize