perlbrew: moving to a new perl with all current modules

Given a perlbrew + cpanm setup (which now I can not possibly imagine my toolbox without), a quick dirty/useful way to switch perls and restore all modules in minutes - without an elaborate/proper @INC scan - is to use perllocal:

1. Gather:

perldoc -t perllocal | perl -lane'/"Module"/ && print $F[-1]' | sort -
+u >/tmp/pms
[download]

2. Switch:

perlbrew switch perl-5.42.0
[download]

cpanm -v </tmp/pms &>>/tmp/inst.log & tail -f /tmp/inst.log
[download]

Update: moritz++ for the list argument reminder and kcott++ for the logfile suggestion. Prev. was
cat /tmp/pms | while read module ; do cpanm -v $module ; done
[download]
(yes, I prefer the useless cat :) - I like the award!)

perl -MLWP::Simple -e'print$_[rand(split(q.%%\n.,
get(q=http://cpan.org/misc/japh=)))]'
[download]

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Re: perlbrew: moving to a new perl with all current modules by kcott (Archbishop) on Jun 13, 2012 at 06:01 UTC
++ I liked the overall technique you've used here. Here's a few thoughts: "... restore all modules in minutes ... " - I question the time you estimate here; although, as I don't use `cpanm`, I'm happy to be advised otherwise. Is there a reason for `sort` in the 1st line? I might have used: `s/sort -u/uniq/`. The output from the 3rd line is likely to be quite lengthy. Consider adding `> /tmp/pms_out 2>&1`. You can use `tail -f` if you want to view the output and you have a full history if anything goes wrong. Update: `s/is you want/if you want/` -- Ken	[reply] [d/l] [select]
Re^2: perlbrew: moving to a new perl with all current modules by zgrim (Friar) on Jun 13, 2012 at 12:54 UTC
Yes, the time estimate might be optimistic, depends on many things, of course, module list size, disk & network speed, cpu, etc. The important thing is it is non-interactive, you don't have to sit around answering author questions :) (eg: just hitting Enter some 2h later - when coming back to it - to a "stuck" (Y/n)) so in the end it just might *feel* faster, given you are free to do other important things (eg: coffee/tea) meanwhile. Skipping tests makes it way faster (cpanm -n), but let noone hear us, it's frowned upon with good reason. :) I prefer the sort for two small reasons, 1. eases a bit the visual inspection before install, and 2. upon progress inspection you might wanna know which letter it's at, has an irrational but human "progress bar" feel to it. :) Sure, you can output to some log and tail it, `cpanm -v </tmp/pms &>>/tmp/inst.log & tail -f /tmp/inst.log` , but i usually just hit M-s error in my urxvtc. -- `perl -MLWP::Simple -e'print$_[rand(split(q.%%\n., get(q=http://cpan.org/misc/japh=)))]'` [download]	[reply] [d/l] [select]
Re: perlbrew: moving to a new perl with all current modules by moritz (Cardinal) on Jun 13, 2012 at 08:02 UTC
Or even `cat /tmp/pms \| xargs cpanm`, since cpanm accept multiple modules to install on its command line. I also have a local CPAN mirror set up with CPAN::Mini, which greatly reduces installation time of modules. (And no, for bigger installations that still takes more than a minute, but the manual effort is just a minute). Perl 6 - the future is here, just unevenly distributed	[reply] [d/l]
Re^2: perlbrew: moving to a new perl with all current modules by tobyink (Canon) on Jun 17, 2012 at 10:17 UTC
Some operating systems (e.g. Linux) place an arbitrary limit on the length (in bytes) of the argument list passed to a process. See Linux ARG_MAX. `perl -E'sub Monkey::do{say$_,for@_,do{($monkey=[caller(0)]->[3])=~s{::}{ }and$monkey}}"Monkey say"->Monkey::do'`	[reply]
Re^3: perlbrew: moving to a new perl with all current modules by moritz (Cardinal) on Jun 17, 2012 at 10:48 UTC
... and xargs is well aware of that, and splits up the command line and executes the program multiple times if necessary. Perl 6 - the future is here, just unevenly distributed	[reply]
Re^4: perlbrew: moving to a new perl with all current modules by morgon (Priest) on Jun 17, 2012 at 10:50 UTC
Re^5: perlbrew: moving to a new perl with all current modules (xargs) by moritz (Cardinal) on Jun 17, 2012 at 13:45 UTC


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