Appending in a switch case statement

diffredential has asked for the wisdom of the Perl Monks concerning the following question:

Dear Monks, I have a very simple idea, having a 'go' command, that cd's to the most used directories. As I want to 'go' in the shell , I need to write it as a shell function. So, in the .bashrc file I have:


function go
{
        case $1 in
          (tmp)  cd $HOME/tmp;;
          (home) cd $HOME/home;;
          
         esac
}
[download]

So I can 'go tmp', 'go home' in the shell and I will go. OK. So say I want to add a new route, I have to append a new statment on the switch case, say:

function go
{
        case $1 in
          (tmp)  cd $HOME/tmp;;
          (home) cd $HOME/home;;
          (fd)   cd $HOME/foodir;;
         esac

}
[download]

With requires editing the .bashrc file. I would love to do instead(on the shell):

go --add fd $HOME/foodir
[download]

so the .bashrc file is edited the way I would do it (shown above). Then my approach is, of course, editing the file:

function go
{
        if [ $1 = "--add" ];then
             
            perl -pi -ne 's/UNKNOWN/($2) cd $3;;/' ~/.bashrc
            
        fi

        case $1 in
          (tmp)  cd $HOME/tmp;;
          (home) cd $HOME/home;;

         esac

}
[download]

And here comes the extreme power of perl regex. I've been trying to solve the correct regex that would append a new entry on the switch case, but had no luck. If only you monks could help me getting this job done :)

Comment on Appending in a switch case statement Select or Download Code

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Re: Appending in a switch case statement by ikegami (Patriarch) on Dec 20, 2008 at 20:43 UTC
Sounds like you want `CDPATH`. Given the following entry in `.bash_profile`, `export CDPATH=.:~:~/www:~/tmp` [download] you get the desired behaviour with `cd`: `[~]$ cd bin /home/ikegami/bin [~/bin]$ cd lib /home/ikegami/lib [~/lib]$ cd example.com /home/ikegami/www/example.com [~/www/adaelis.com]$` [download] It'll save you from writing a bash parser (although a half-assed one should work).	[reply] [d/l] [select]
Re: Appending in a switch case statement by ikegami (Patriarch) on Dec 20, 2008 at 21:02 UTC
Now to answer your question directly. Adding guide comments simplifies the matter and makes it more reliable. function go { if [ $1 = "--add" -o $1 = "--rem" ] ; then perl -e' use strict; use warnings; my ($key, $dir) = @ARGV; local $^I = ".bak"; local @ARGV = "$ENV{HOME}/.bashrc"; while (<>) { my $f = /^\s# -- BEGIN GO CASES --/ .. /^\s# -- END GO CASES --/; if (!$f \|\| $f == 1) { } elsif ($f !~ /E/) { $_ = "" if /^\s$\Q$key\E$/; } elsif ($dir) { my ($prefix) = /^(\s)/; print("$prefix($key) cd $dir;;\n"); } } continue { print } ' $2 $3 else case $1 in # -- BEGIN GO CASES -- (tmp) cd $HOME/tmp;; (home) cd $HOME/home;; # -- END GO CASES -- esac fi } [download] Update: Switched to the desired syntax. `go --add shortcut dir (replaces if it already exists) go --rem shortcut go shortcut` [download] I only tested the Perl components. The bash components were assumed to be correct. Update: Fixed bug in `if [ ... ]`.	[reply] [d/l] [select]
Re: Appending in a switch case statement by zwon (Abbot) on Dec 20, 2008 at 21:53 UTC
Maybe something like this `function go { if [ $1 = "--add" ];then perl -pi -ne 's/^\(UNKNOWN/($2) cd $3;;\n(UNKNOWN/' ~/.bashrc fi case $1 in (tmp) cd $HOME/tmp;; (home) cd $HOME/home;; (UNKNOWN) true ;; esac }` [download] Though actually I don't like the idea	[reply] [d/l]
Re: Appending in a switch case statement by diffredential (Beadle) on Dec 20, 2008 at 22:06 UTC
Thanks so much :D!! ikegami I'll take a look at CDPATH!! And the script you attached works perfectly!! amazing!! Thanks again :)	[reply]
Re: Appending in a switch case statement by rir (Vicar) on Dec 22, 2008 at 20:05 UTC
<Update> I meant to include my reason for not just using CDPATH. I play around in directory trees like: `$HOME/<projectname>/(source\|target)/<modulename>/CPAN_structured_tree` where I am usually in the bottom of one project's source tree, and occasionally want to jump to the sister-directory in the target or into the source of a different project. I use shell history and a few exported variable names for directories. </Update> For background, I ran across this cute `alias` which I never use: `realias='$EDITOR ~/.aliases; source ~/.aliases'` [download] In the case you give, I use exported variables and `cd`. I've never felt the need to have my environment evolve so rapidly that I couldn't use an editor in a spare screen to edit my `.bashrc`. So I would just: `$ export tmp=/tmp $ cd $tmp` [download] To make this more suited to your style, I'd blend this together into something like: `function reexport { echo export "$*" >> $HOME/.exports; source $HOME/.exports; }` [download] Given that you perl, perhaps you can stand some dollar signs. Be well, rir	[reply] [d/l] [select]
Re: Appending in a switch case statement by gube (Parson) on Dec 25, 2008 at 16:34 UTC
Simply you can use this below code as well in .basrc `function go { case $1 in (dashboard) cd $HOME/dashboard;; (2.8) cd $HOME/dashboard/2.8;; ($1) cd $HOME/$1;; esac; }` [download] It will take to your $HOME directory default and from their your path, i meant instead "cd ~/<directories>" :-)	[reply] [d/l]