How do I display the exit status of the last command in bash?

indigowinged

Man page for bash - GNU Bourne-Again SHell

Commands that complete without errors exit with a status of number zero meaning it completed successfully and without issues. For example:

$ pgrep systemd
1
635
667
828
926
1328
2237

Check the exit status immediately after.

echo $?
0

If the command does not complete successfully the exit status will be non-zero. Here the number one exit status number, means, No processes matched or none of them could be signalled.

$ pgrep systemddd
$ echo $?
1

You would expect this as there is no such command systemddd and pgrep could not find it.