Piping data in on the command line

ruby-talk
1

Hello all,

I know you can get command line args using ARGV, but is there a way to use
the '<' operator to pipe data into your program, as in

ruby myprog.rb < ~/myfile.txt

···

--
James Coglan

2

I know you can get command line args using ARGV, but is there a way to use
the '<' operator to pipe data into your program, as in

AFAIK that's called I/O redirection.

ruby myprog.rb < ~/myfile.txt

$ ruby cat.rb < cat.rb
puts *ARGF

regards, Sandor Szücs

···

On 09.07.2008, at 09:22, James Coglan wrote:
--

3

Just read the IO $stdin, like:

$stdin.each { |line| puts "Found: #{line}" }

The < "operator" is a shell feature that will pass the content of a file to
the programs standard input (stdin).

martin

···

On Wednesday 09 July 2008 08:22:15 James Coglan wrote:

Hello all,

I know you can get command line args using ARGV, but is there a way to use
the '<' operator to pipe data into your program, as in

ruby myprog.rb < ~/myfile.txt

4

Maybe that's more readable, but my point wasn't the shell feature < .
cat.rb has one line:
puts *ARGF

$ ruby cat.rb < cat.rb
puts *ARGF

regards, Sandor Szücs

···

On 09.07.2008, at 14:34, Martin Boese wrote:

Just read the IO $stdin, like:

$stdin.each { |line| puts "Found: #{line}" }

The < "operator" is a shell feature that will pass the content of a file to
the programs standard input (stdin).

--

5

Thank you both. If anyone is the least bit interested I'm writing myself yet
another commandline option parser:

It's inspired by trollop, but it has some more option types and is more
easily extensible, automates a few extra things (like recognizing
--no-verbose if you've got a --verbose option for example) and it generates
slightly nicer (more man-page-like) help text.

···

2008/7/11 Sandor Szücs <sandor.szuecs@fu-berlin.de>:

On 09.07.2008, at 14:34, Martin Boese wrote:

Just read the IO $stdin, like:

$stdin.each { |line| puts "Found: #{line}" }

The < "operator" is a shell feature that will pass the content of a file
to
the programs standard input (stdin).

Maybe that's more readable, but my point wasn't the shell feature < .
cat.rb has one line:
puts *ARGF

6

you may be interested in

  http://codeforpeople.com/lib/ruby/main/main-2.8.1/README

  http://codeforpeople.com/lib/ruby/main/main-2.8.1/samples/

gem install main

the whole concept is to obviate the notion of ever parsing options

cheers.

a @ http://codeforpeople.com/

···

On Jul 11, 2008, at 10:59 AM, James Coglan wrote:

Thank you both. If anyone is the least bit interested I'm writing myself yet
another commandline option parser:

GitHub - jcoglan/oyster: Command-line input parser that doesn't hate you

It's inspired by trollop, but it has some more option types and is more
easily extensible, automates a few extra things (like recognizing
--no-verbose if you've got a --verbose option for example) and it generates
slightly nicer (more man-page-like) help text.

--
we can deny everything, except that we have the possibility of being better. simply reflect on that.
h.h. the 14th dalai lama