Command History – How to Get Command Name of the Last Executed Command

The PID of the last executed command is in the $! shell variable:

my-app &
echo $!

If you are using bash, you can use the fc command to display your history in the way you want:

fc -ln -1

That will print out your last command. -l means list, -n means not to prefix lines with command numbers and -1 says to show just the last command. If the whitespace at the start of the line (only the first line on multi-line commands) is bothersome, you can get rid of that easily enough with sed. Make that into a shell function, and you have a solution as requested (getlast >> LOGBOOK):

getlast() {
    fc -ln "$1" "$1" | sed '1s/^[[:space:]]*//'
}

That should function as you have asked in your question.

I have added a slight variation by adding "$1" "$1" to the fc command. This will allow you to say, for example, getlast mycommand to print out the last command line invoking mycommand, so if you forgot to save before running another command, you can still easily save the last instance of a command. If you do not pass an argument to getlast (i.e. invoke fc as fc -ln "" "", it prints out just the last command only).

[Note: Answer edited to account for @Bram's comment and the issue mentioned in @glenn jackman's answer.]