[Haskell-cafe] Re: wanted: haskell one-liners (in the perl sense of one-liners)

with PCRE. now (and yep, it's a lot faster than posix): *************************************************************************** thartman@linodewhyou:~/learning/haskell/UnixTools$ ./q-words.sh q qua quack quacked quackery quackery's quacking quacks quad quad's real 0m6.691s user 0m2.460s sys 0m3.000s q qua quack quacked quackery quackery's quacking quacks quad quad's real 0m1.032s user 0m0.750s sys 0m0.100s thartman@linodewhyou:~/learning/haskell/UnixTools$ cat q-words.sh time cat /usr/share/dict/american-english | ghc -e 'interact $ unlines. take 10 . filter ( \x -> x =~ "^q" :: Bool ) . lines' ImportsRegexPosix.hs time cat /usr/share/dict/american-english | ghc -e 'interact $ unlines. take 10 . filter ( \x -> x =~ "^q" :: Bool ) . lines' ImportsRegexPCRE.hs thartman@linodewhyou:~/learning/haskell/UnixTools$ cat ImportsRegexPosix.hs import Text.Regex.Posix thartman@linodewhyou:~/learning/haskell/UnixTools$ cat ImportsRegexPCRE.hs import Text.Regex.PCRE thartman@linodewhyou:~/learning/haskell/UnixTools$ 2007/3/7, Thomas Hartman :

In the spirit of making easy things easy, here is a "haskell from shell" one-line grepper, that uses regexen.

Now, if only I could get pcre-regex installed I would be quite content. (Still stuck using posix RE for now.)

**************

thartman@linodewhyou:~/learning/haskell/UnixTools$ time ./q-words.sh q qua quack quacked quackery quackery's quacking quacks quad quad's

real 0m3.186s user 0m1.900s sys 0m0.810s

thartman@linodewhyou:~/learning/haskell/UnixTools$ cat q-words.sh cat /usr/share/dict/american-english | ghc -e 'interact $ unlines. take 10 . filter ( \x -> x =~ "^q" :: Bool ) . lines' Imports.hs

thartman@linodewhyou:~/learning/haskell/UnixTools$ cat Imports.hs import Text.Regex.Posix

****************************

2007/3/2, Thomas Hartman :

...

Okay, I am aware of

http://haskell.org/haskellwiki/Simple_unix_tools

which gives some implementation of simple unix utilities in haskell.

But I couldn't figure out how to use them directly from the shell, and of course that's what most readers will probably wnat.

Or let me put it another way.

Is there a way to do

find -maxdepth 1 -type f | xargs du | perl -ane 'print "\$F[0]\n"' | perl -e '$sum += $_ while <>; print "$sum\n"'

as a shell command that idiomatically uses haskell?

For non-perlers, that sums up the disk usage of all files in the current directory, skipping subdirs.

print "\$F[0]\n

looks at the first (space delimited) collumn of output.

perl -e '$sum += $_ while <>; print "$sum\n"'

, which is I guess the meat of the program, sums up all the numbers spewed out of the first column, so in the end you get a total.

So, anyone out there want to establish a haskell one liner tradition?

:)

thomas.