How Ruby is beating Python in the battle for the Soul of System Administration

Re:How Ruby is beating Python in the battle for the Soul of ... by bad_user on Monday October 03, 2011 @07:27AM (#3065868)

     Last 10 lines in a file? 'tail -10 filename.txt'

A lot uglier, but you can do a one liner ...

     ruby -e 'lines=[]; while gets(); lines << $_; \
       lines = lines[-10,10] unless $. < 10; end; \
       puts lines' < filename.txt

The problem with using "the right tool for the right job" is that there are many tools and many jobs, and a general purpose language helps you get things done in case you're stuck. In general I use Ruby for doing string manipulation before piping to other commands.

Here's an (ugly) one liner that shows the biggest tables in a MySQL database:

     mysql -u root godzilla -s -e 'show tables' \
     | ruby -ne '$_.strip!; puts %Q{SELECT count(*) \
       as cnt, "#$_" as tbl FROM #$_; }' \
     | mysql -u root godzilla -s \
     | sort -nr \
     | ruby -ne 'parts = $_.split /\s+/; \
       puts "%40s : %s" % parts.reverse' \
     | head -10

You can probably come up with something more clever, but I barely gave that one any thought.

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Re:How Ruby is beating Python in the battle for the Soul of ... by jbert on Monday October 03, 2011 @09:33AM (#3066190)

> A lot uglier, but you can do a one liner ...

Yeah, but that one-liner reads the whole file. 'tail' can be more clever (and is). 'strace' output:

    open("a", O_RDONLY)                     = 3
    fstat(3, {st_mode=S_IFREG|0644, st_size=545975512, ...}) = 0
    lseek(3, 0, SEEK_CUR)                   = 0
    lseek(3, 0, SEEK_END)                   = 545975512
    lseek(3, 545972224, SEEK_SET)           = 545972224
    read(3, "tu 11.04 \\n \\l\n\nUbuntu 11.04 \\n "...,     3288) = 3288

'tail' is seeking to the end, then reading backwards.

The point being, these 'little tools' can contain important optimisations - they aren't necessarily equivalent to a naive reimplementation.

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Re:How Ruby is beating Python in the battle for the Soul of ... by lloeki on Monday October 03, 2011 @11:06AM (#3066537)

Reminds me on that article on GNU grep doing some speedy magic: http://lists.freebsd.org/pipermail/freebsd-current/2010-Augu...

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