RE: modules: shell portabililty?

[Dave H. <hi...@es...>]

Hi to all and to you two that responded ...


The overall idea is that I want the aliases to work no matter what the user
shell is,
AND I don't want to have to be aware of the level of detail you'll read
about below
in order to create portable aliases.  The 'addpath' example cannot be done
as
a separate script (environment variable inheritance is thankfully one way),
so
it must be an alias/function. Here is the code in the modulefiles I came up
with.

Example 1:
This is a simple alias with a parameter - no problem - works for any shell
because it's semantically simple enough.
set-alias ls {ls -F}

Examples 2:

This code makes an addpath alias and a 'col' alias.
The addpath alias is supposed to add something to your path, functionality I
want available to the person who loads the module;
and the col alias is supposed to return the nth word of each line of stdin.

if { [ module-info shelltype ] == "csh" } {
        set-alias addpath { set path ( \$path $1 ) }
 
        # the following is what happens when your code has to run
        # through the tcl parser,
        # then the csh to create the alias,
        # and then the csh again whenever the alias is used
 
        # start with this:
        set-alias col [join { {awk '"'} "\{" {print "'\$''\\!\\!:1'"} "\}"
{'"} {'} } ""]
        # set-alias runs this through the tcp interpreter, and inserts it
        # between the single quotes in the string
        #       alias col ''
        # which means that my expression must allow for these 'helpful'
        # single quotes by assuming they'll be there.  The result is
        #       alias col 'awk '"'{print "'$''\!\!:1'"}'"''
        # which means that the runtime shell sees (when you type 'col n')
        #        awk '{print $!!:1}'
        # which means, make awk show us the nth column of the stdin.
  } else { # assume ksh, bash or sh
        # there simply is a different syntax for doing this.
        set-alias addpath { PATH=$PATH:$1 }

        # Fro the col alias, sh type quoting is much easier to deal with,
but *different*, so I start with a different expression.
        set-alias col { awk '\{ print $'$1' \}' }

        # tcl interprets this down to the single word: awk '{ print $'$'1}'
        # which is fed to the current shell in in an 'eval'
        # with the result that the alias is defined as something that looks
the same but has word
        # breaks where they need to be, and works when the user types 'col
n'
}