What information is shown by the echo $? command?

The correct answer is B. The exit value of the command executed immediately before echo. $? is a special shell variable that holds the exit status of the most recently executed command - a value of 0 means success, and any non-zero value indicates an error. When you run echo $?, the shell expands $? before echo runs, so what gets printed is the exit status of…

Shells and Shell Scripting

Question

What information is shown by the echo $? command?

Options

AThe process ID of the echo command.
BThe exit value of the command executed immediately before echo.
CThe process ID which will be used for the next command.
DThe exit value of the echo command.
EThe process ID of the current shell.

How the community answered

(51 responses)

A
2% (1)
B
82% (42)
C
4% (2)
D
10% (5)
E
2% (1)

Explanation

$? is a special shell variable that holds the exit status of the most recently executed command - a value of 0 means success, and any non-zero value indicates an error. When you run echo $?, the shell expands $? before echo runs, so what gets printed is the exit status of whatever command ran before the echo.

Why the distractors are wrong:

A & C - $? has nothing to do with process IDs. The variable for the current shell's PID is $$, and there's no built-in variable for the "next" PID.
D - This is the subtle trap: by the time echo executes, $? has already been replaced with the previous command's exit value. You're not capturing echo's own status.
E - The current shell's PID is $$, not $?.

Memory tip: Think of $? as "what happened?" - it answers whether the last command succeeded or failed, like checking the result of the previous action before moving on.

Topics

#exit status#shell variables#$?#command execution

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