Howto use parameters in a function or alias in .bashrc on ubuntu?

Question

For example this does not work:

man(){ man -H "$1" & }

But I need the parameter, because I want the command to end with an ampersand.

This doesn't work as well:

man(){ firefox & man -H }

I don't want firefox to close if the firefox process is started by man and man is terminated.

If you hadn't deleted your prior question, I would have finished extending my answer there. — Charles Duffy
– Charles Duffy, Commented Sep 23, 2016 at 17:28
BTW, expounding on "does not work" is generally a good idea. What does it do? How do you know it doesn't work? Have you run type man to ensure that it's actually defined in your current shell instance? Etc. — Charles Duffy
– Charles Duffy, Commented Sep 23, 2016 at 17:29
BTW, what follows -H is supposed to be the name of your browser. I assume you'd want man() { man -H /path/to/firefox "$@" & }, or such, instead. — Charles Duffy
– Charles Duffy, Commented Sep 23, 2016 at 17:31
and even then, that won't have any effect unless the man page you want is actually in HTML format, so I'm not sure why running man -H ...anything... & is ever a thing you'd actually want to do. — Charles Duffy
– Charles Duffy, Commented Sep 23, 2016 at 17:31
Also? Use set -x to make your shell log what it's doing to stderr (or the file descriptor pointed at with BASH_XTRACEFD on 4.x, if you want to redirect it to a log file -- which is actually a good idea, if man is being invoked). If you think it's not actually running the function, put that command first, and see if that's true. — Charles Duffy
– Charles Duffy, Commented Sep 23, 2016 at 17:33

Charles Duffy · Accepted Answer · 2016-09-23 18:37:29Z

The parameter isn't a problem. The recursion is the (most severe immediate) problem.

When you have a function named man call man, it calls itself. You're starting an unbounded set of background shells. Using command will prevent that recursion, as it bypasses function lookup.

One change I would suggest making with respect to parameter-passing is using "$@", so the full set of parameters is passed through, not only the first one:

man() { command man -H "$@" & }

Note, by the way, that at least for the BSD implementation used by Apple, man -H expects the name of a program that can convert HTML to text to be the immediate following argument. If you think that, for instance, man -H bash & will start the bash man page in a web browser in the background... well, that may be the case on your platform, but it's not universally true.

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