On 2004-05-09 21:12:56 -0400, alex wrote:
> All I can say is that the aliases that I use have worked very
> well for me and I could't detect any difference in the results
> between the aliases and functions. Could you please elaborate
> on why functions are preferable to aliases for compound commands?
If you add arguments or something else (a redirection or a & for
instance) after the alias in the command line, this will apply
to the last command.
Here's another example:
ay:~> alias foo='ls -R > bar; date'
ay:~> foo &
This is equivalent to
ls -R > bar
date &
not
{ ls -R > bar; date } &
(This is the zsh syntax, I don't know about the other shells.)
> All I know about Linux has been gleaned from the lists and web
> pages so this is a bit too cryptic for my meager education.
> Could you please give a few details or point me to where
> there's an explanation?
Well, here an analogy with mathematics. You can write c = a + b
and you consider c * d. If you regard "c = a + b" as a string
replacement, then c * d would mean a + b * d; this is how aliases
work. If you regard "c = a + b" as an expression definition or an
equality (the normal case in math, but this should also be the
case in Unix shells), then c * d means (a + b) * d.
Aliases are just string replacements. Functions are much more
structured (very similar to shell scripts).
In a shell, if I type "foo", this is just like a command and I also
expect that "foo &" would start something in the background. Ditto
for "foo > file": I expect all the output of foo to be redirected
to file.
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