get options with getoptlong

install:

~# gem install getopt
Successfully installed getopt-1.3.7
1 gem installed
Installing ri documentation for getopt-1.3.7...
Installing RDoc documentation for getopt-1.3.7...

need: require 'getoptlong'

#!/usr/bin/ruby

require 'getoptlong'

opts = GetoptLong.new(
   [ "--test",             "-t",   GetoptLong::REQUIRED_ARGUMENT ],
   [ "--blub",             "-b",   GetoptLong::OPTIONAL_ARGUMENT ],
   [ "--help",             "-h",   GetoptLong::NO_ARGUMENT ],
   [ "--usage",            "-u",   GetoptLong::NO_ARGUMENT ],
   [ "--version",          "-v",   GetoptLong::NO_ARGUMENT ]
)

opts.each do |opt, arg|
 case opt
   when "--test"
     puts "we must extract :#{arg}:"
   when "--blub"
     puts "blub blub : #{arg} :"
   when "--help"
     puts "help yourself"
   when "--usage"
     puts "getoiptlong.rb"
     puts " -t, -b, -h, -u , -v"
   when "--version"
     puts "version 0.01"
   else
     puts "upsala"
 end
end

print out file wiht numbers of line

#!/usr/bin/ruby
# put out file wiht numbers out
#

file=ARGV[0] 

begin
  lines=File.open(file, "r").readlines
  format="%0#{lines.size.to_s.size}d"
  lines.each_with_index { |l, i|
    puts "#{sprintf(format, i+1)}: #{l}"
  }
rescue
  puts "no file???   or errors"
end

print out environment variables

ENV.each do |e|
p e
end

ENV: array of arrays

p: something like print or puts but better, doesn't interpolate!

ENV.each: iterate in a block each item of array ENV

do .. end: blocks

|e|: pipe, there is the block parameters


example:
["SHELL", "/bin/bash"]
["TERM", "xterm"]

create executable file, which extract a directory

umwandeln Inhalt eines Verzeichnisses in eine ausführbare Datei. die sich selbst in
ein Verzeichniss extrahiert

Lösung

download a page and print out links

webseite runterladen und links ausgeben

Hilfslinks:
http://snippets.dzone.com/posts/show/788
http://www.example-code.com/ruby/rubyhttp.asp


Lösung:

 #!/usr/bin/ruby

 require 'net/http'

 if ARGV.length >0
   url=ARGV[0]
 else
   p " url file"
   Process.exit
 end

 req = Net::HTTP.get_response(URI.parse(url))
 line=req.body

 lines=line.split(" ")

 lines.each do |l|
   if l.include?("href=http") or l.include?("href=\"http")
     v1=l.split("\"")
     if v1.length>1
       puts v1[1]
     else
       puts v1[0]
     end
   end
  
 end

replace word in a file

ein Replace-programm für Datei erstellen.
ein Wort durch ein anderen ersetzen

Lösung:

 #!/usr/bin/ruby

 puts "start"

 if ARGV.length > 2
   datei=ARGV[0]
   muster=ARGV[1]
   ersetzen=ARGV[2]
 else
   print "\n\tfile02.rb  file muster replacetext\n\n"
   Process.exit
 end

 puts "mustering file #{datei}"

 f=File.open(datei, "r+")
     lines = f.readlines           # read into array of lines
     lines.each do |it|            # modify lines
         it.gsub!(/#{muster}/, ersetzen)
     end
     f.pos = 0                     # back to start
     f.print lines                 # write out modified lines

     f.truncate(f.pos)  
 f.close

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