About this series: A collection of short blog posts about lcpan tips/recipes. Some posts will also end up in the upcoming App::lcpan::Manual::Cookbook POD to be included in the App::lcpan distribution. First article is here. See the whole series.
About lcpan: an application to download and index a mini CPAN mirror on your local filesystem, so in effect you will have something like your own CPAN with a command-line tool (or perl API) to query and extract information from your mirror. I find it perfect for my own personal use when working offline.
lcpan remains as one of my most-used tools when doing Perl/CPAN development. I use it to search for modules to do some task (usually when I am offline or too lazy to open a browser tab to MetaCPAN, but also to do some grep-ing against the search results). I also use it sometimes to find modules related to a specific module, as keyword searches or seeing the SEE ALSO section of PODs are sometimes insufficient.
The following is a simplistic shell history analysis on how I use lcpan (on my main laptop, at least). The history I have on my laptop is from Nov 2017 to Jan 2019, so that more or less reflects how I used lcpan during 2018.
lcpan and lcpanm
% history | perl -lne's/.+?\]//; s/^pg //; next unless /^lcpanm?\s/; s/(^\S+).*/$1/; print' | freqtable 459 lcpan 332 lcpanm
I install modules from local mirror using lcpanm quite often.
PAGE_RESULT=1
"pg " is a shell alias which I define as:
alias pg='PAGE_RESULT=1'
because that lets me navigate the output of lcpan with a PAGER (which I have defined as 'less -FRSX').
Most often used subcommands
% history | perl -lne's/.+?\]//; s/^pg //; next unless /^lcpan\s/; s/(^\S+ \S+).*/$1/; print' | freqtable 175 lcpan mods 107 lcpan doc 35 lcpan scripts 32 lcpan deps 17 lcpan rdeps 16 lcpan related-mods 14 lcpan src 11 lcpan stats-last-index-time 10 lcpan upd ...
I use lcpan most often to:
- search for modules (lcpan mods);
- read documentation of modules which I don't have installed yet (lcpan doc);
- search for scripts (lcpan scripts);
- see dependencies (lcpan deps);
- see reverse dependencies (lcpan rdeps);
- search for related modules (lcpan related-mods);
- see source code of modules I don't have installed yet (lcpan src);
- checking the last update date of the index (lcpan stats-last-index-time);
- updating the mirror/index (lcpan upd which is shortcut for lcpan update).
Finding modules
% history | perl -lne's/.+?\]//; s/^pg //; next unless /^lcpan mods\s/; print' | sort -u lcpan mods lcpan mods average lcpan mods average -l lcpan mods average|wc -l lcpan mods binary search -l lcpan mods bitfin lcpan mods bitflip lcpan mods bitgrail lcpan mods bloomberg lcpan mods bluetooth lcpan mods bluetooth -l lcpan mods b perlstring lcpan mods ccxt lcpan mods cpan release lcpan mods cpan release -l lcpan mods DateTime::Format lcpan mods DateTime::Format duration lcpan mods DateTime::Format::Japanese lcpan mods datetime iso8601 lcpan mods datetime iso8601 -l lcpan mods dbi string lcpan mods dbi string -l lcpan mods dbi table lcpan mods dbi table -l lcpan mods Dist::Zilla::Plugin add -l lcpan mods Dist::Zilla::Plugin:: --author PERLANCAR -l lcpan mods Dist::Zilla::Plugin Module lcpan mods Dist::Zilla::Plugin Module -l lcpan mods eval lcpan mods eval -l lcpan mods fifo -l lcpan mods File::Slurper lcpan mods File::Slurper -l lcpan mods finance crypto lcpan mods float util lcpan mods histo lcpan mods histog -l lcpan mods histogr -l lcpan mods histo -l lcpan mods inside eval -l lcpan mods interpo lcpan mods inventory lcpan mods inventory -l lcpan mods inventory|wc -l lcpan mods -l array rank lcpan mods -l bin groups lcpan mods -l c encode lcpan mods -l cli hub lcpan mods -l compare lcpan mods -l data cmp lcpan mods -l dbi csv lcpan mods -l dbix conn lcpan mods -l dbix shortcut lcpan mods -l freq table lcpan mods -l groups lcpan mods -l http tiny lcpan mods -l list rank lcpan mods -l module abstract lcpan mods -l module info lcpan mods -l module pod lcpan mods -ln role lcpan mods -l ord lcpan mods -l ordina lcpan mods -l ordinaq lcpan mods -l permute lcpan mods -l pod abstract lcpan mods -l Regexp::Common:: lcpan mods -l Regexp::Pattern lcpan mods -l return level lcpan mods -l stock exchange lcpan mods -l test2 tool lcpan mods -l Test::Approximate lcpan mods -l test compare lcpan mods -l Test::Deep:: lcpan mods -l throttle lcpan mods -l Tickit lcpan mods -l Tickit Grid lcpan mods -l tie array lcpan mods -l Versioning dot lcpan mods -l who lcpan mods --namespace Acme::CPANLists lcpan mods --namespace Acme::CPANLists -l lcpan mods --namespace Acme::CPANModules -l lcpan mods --namespace Acme::CPANModuless -l lcpan mods --namespace Bencher -l lcpan mods --namespace Bencher::Scenario lcpan mods --namespace Bencher::Scenario -l lcpan mods --namespace Data::Sah::Coerce::perl lcpan mods --namespace Data::Sah::Coerce::perl::str lcpan mods --namespace DateTime::Format lcpan mods --namespace DateTime::Format -l lcpan mods --namespace Graphics::ColorNames lcpan mods --namespace Graphics::ColorNames|xargs lcpanm -n lcpan mods --namespace Log::ger lcpan mods --namespace Log::Ger lcpan mods --namespace Log::ger|grep -i dump lcpan mods --namespace String -l lcpan mods --namespace WordList::Char lcpan mods -n Archive::Tar lcpan mods -n digit lcpan mods -n digit -l lcpan mods -n digit|wc -l lcpan mods nearest -l lcpan mods near -l lcpan mods -n fifo lcpan mods -n generic lcpan mods -n generic -l lcpan mods -nl Archive::Tar lcpan mods -nl gen pw lcpan mods -nl genpw lcpan mods -nl pass gen lcpan mods -nl pwd gen lcpan mods -n pass gen lcpan mods -n permute digit lcpan mods Number::Format lcpan mods Number Format -l lcpan mods Number::Format -l lcpan mods pass templat lcpan mods pass templat -l lcpan mods percent lcpan mods percent Sah lcpan mods percent|wc -l lcpan mods perinci usage lcpan mods perl release -l lcpan mods permute lis lcpan mods purchase lcpan mods purchase -l lcpan mods purchase price lcpan mods python -l lcpan mods qr decode lcpan mods qr decoded lcpan mods random norm -l lcpan mods redact lcpan mods regexp common lcpan mods regexp common cc lcpan mods regexp common credit lcpan mods regexp common -l lcpan mods ssh client -l lcpan mods stack trace -l lcpan mods stock lcpan mods stock -l lcpan mods stock|wc -l lcpan mods Test::Deep:: -l lcpan mods test path lcpan mods Text::Histogram lcpan mods time -l lcpan mods time of day -l lcpan mods timeofday -l lcpan mods version dot lcpan mods version scheme lcpan mods version scheme|grep -v Google lcpan mods who -l lcpan mods WordList::CryptoCurrency::Catalog::Name
I do keyword searches a lot, and when the keyword is not specific enough I usually add "pg" and "-l" to let me navigate and search further with less. Sometimes I also do namespace searching (--namespace). I search for my own modules a lot, usually because I forget the exact name.
Finding related modules
Modules I tried to find related modules of:
% history | perl -lne's/.+?\]//; next unless /^lcpan related-mods\s/; print' | sort -u
; lcpan related-mods alias::module
lcpan related-mods Data::Diff lcpan related-mods Data::Throttler lcpan related-mods Data::Valve lcpan related-mods IO::Tee lcpan related-mods Number::Tolerant lcpan related-mods Package::Alias lcpan related-mods String::JS lcpan related-mods Test::Deep lcpan related-mods utf8
Finding scripts
% history | perl -lne's/.+?\]//; s/^pg //; next unless /^lcpan scripts\s/; print' | sort -u lcpan scripts bin -l lcpan scripts count lcpan scripts count -l lcpan scripts dateconv lcpan scripts dateconv -l lcpan scripts envres lcpan scripts group -l lcpan scripts histogram -l lcpan scripts http-tiny lcpan scripts interval lcpan scripts interval -l lcpan scripts lineno lcpan scripts linenum lcpan scripts line number lcpan scripts lino lcpan scripts linum lcpan scripts -l org2html lcpan scripts -l org-to-html lcpan scripts parse-nik lcpan scripts parse-nik -l lcpan scripts parse num lcpan scripts _pause lcpan scripts perl lcpan scripts perllint lcpan scripts pick lcpan scripts pick -l lcpan scripts pick-l lcpan scripts rand lcpan scripts rand -l lcpan scripts resolution lcpan scripts resolution -l lcpan scripts throttle lcpan scripts zodiac -l
I search for my own scripts a lot too, since I have almost a thousand (~880) of them on CPAN. It's a bit challenging trying to keep the naming organized. When tab completion doesn't help, lcpan comes to the rescue.
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