UNIX for Advanced & Expert Users

Hello everyone

By default, when you create a script and you type it in a terminal, when then you press TAB, it shows you the list of files in the current directory.

But with "nohup", instead, it shows you the commands list.

How could I reproduce the same behaviour with my script please?

Ah, I see what you mean.

In my shell, BASH, I was able to make it work by cheating: I made an alias like alias CMD="nohup cmd" ...and the shell was willing to tab-complete CMD. Which lets me run 'nohup cmd' without nohup stealing the first argument. Just tested it in ksh, it'll tab-complete there too.

héhé ^^ nice trick Corona688 but I would like to understand how "nohup" and "which" commands work ... so
BUMP

Well, the shell always assumes the first argument is a program or builtin -- a safe guess, anything else would be invalid. The following arguments are assumed to be either local files or parameters totally unrelated to files -- usually a safe guess, since you wouldn't expect cat to open /bin/data when you tell it cat data.

But "nohup" looks in ${PATH} because it's designed to run global programs. It's special. It's a convenience program that lets you tack a 'nohup' onto the beginning of a command without otherwise modifying the statement. It works by closing all its own files, then replacing itself with the command you asked it to run, keeping the same set of open files. (This is how all shell redirection works, incidentally -- clone yourself, set up redirection as you want it in the clone, then the clone replaces itself with whatever you wanted run. This is also why you can't redirect a program that's already running.) The shell isn't aware of this behavior, and can't really be made aware of it.

There's a few other nohup-like commands like nice and strace and time, which all do various changes to a program's runtime environment before allowing it to run; nice reduces priority (i.e. makes it behave "nicer"), strace call-traces the program and prints all system calls to stderr, and time tracks the system/user/etc time a program consumes as it runs.

time is usually a builtin and not a real command, but even then she shell isn't smart enough to tab-complete time ca into time cat.

thank you very much Corona688 for this complete explanation

finally I've found an academic way ^^
in fact there is a file /etc/bash_completion
which manages the completion in your bash shell.

In it , I search for "nohup", nice and so
I copy the correponding function and paste it in my .bashrc and of course replace nohup and so by my script name ...

Code:

complete -F _command -o filenames \
cmd1 \
cmd2 \
cmd3

et voilà !!

B-U-T !!! I have a new question now... does someone know a way to make regular expressions work in the .bashrc? for example it'd be cool to write

Code:

cmd[0-9]*

instead of

Code:

cmd1 \
cmd2 \
cmd3

but this doesn't work to