Read file and print contents - beginner

Ruby
1

hello,

im new to ruby and i have a text file and want to read in the file
and print it out.

so far iv got the following. I’d greatly appreciate any help.

thanks.

text file (reference.txt):
Tag: ref1
Type: Book
Author: Little, S R

ruby file:
#!/usr/local/bin/ruby

read file and print

ARGV.each do |fn|
begin
(fn == ‘-’ ? STDIN : File.open(fn)).each_line do |l|
if $indent > 0
(1…$indent).each { print ’ ’ }
end
puts l
end

2

I would change

if $indent > 0
(1…$indent).each { print ’ ’ }
end

to

print ’ ’ * $indent

3

I’ve changed my approach as i dont actually want to count the lines

so i now have this:

ARGV.each do |fn|
begin
(fn == ‘reference.txt’ ? STDIN : File.open(fn)).each_line do |l|
puts l
end

by this im trying to read in the text file and print out its contents

i seem to be getting a load error
any reason why?

thank you

4

On 12/3/07, Johnathan S. [email protected] wrote:

I’ve changed my approach as i dont actually want to count the lines

so i now have this:

ARGV.each do |fn|
begin
(fn == ‘reference.txt’ ? STDIN : File.open(fn)).each_line do |l|
puts l
end

ARGV.each will iterate through every parameter you pass. Since your
script is so simple, you’re better of with ARGV[0]. You’d have to
check the length and see if ARGV.length == 1.

A more Ruby-like approach is this:

#!/usr/bin/env ruby -wKU

if ARGV.length != 1
puts “Syntax is: ruby readfile.rb filename”
exit
end

File.open(ARGV[0], “r”) do |file|
while line = file.gets
puts line
end
end

Using File.open with a block will automatically open and close the
file handler and that’s a pretty decent practice to start with.

I’d highly recommend you the PickAxe book (Programming Ruby, 2nd
edition). It does a great job explaining Ruby concepts (the code above
is just a rip-off from Mr. Thomas’s example on page 129). However,
I’ve heard people complaining that it’s a bit daunting for new
programmers. Maybe you’d feel a bit better with Learning to Program by
Chris P. if words like “iterators” and “inheritance” make you sweat.

5

On Dec 3, 2007 11:16 AM, Johnathan S. [email protected] wrote:

by this im trying to read in the text file and print out its contents

i seem to be getting a load error
any reason why?

thank you

Posted via http://www.ruby-forum.com/.

You’re missing two end lines:

ARGV.each do |fn|
begin
(fn == ‘-’ ? STDIN : File.open(fn)).each_line do |l|
puts l
end
end
end

Sorry, I thought we were just looking at a fragment of your code
before, so I didn’t comment on the missing end lines.