Ruby - Getting Started
| | Ruby user's guide | Getting Started | |
First, you'll want to check whether ruby is installed. From
the shell prompt (denoted here by "%", so don't type the
%), type
(-v tells the interpreter to print the version of ruby),
then press the Enter key. If ruby is installed, you will
see a message something like the following:
% ruby -v
ruby 1.6.6 (2001-12-26) [i586-linux] |
If ruby is not installed, you can ask your administrator to install
it, or you can do it
yourself
, since ruby is free software with no restrictions on its
installation or use.
Now, let's play with ruby. You can place a ruby program
directly on the command line using the -e option:
% ruby -e 'print "hello world\n"'
hello world |
More conventionally, a ruby program can be stored in a file.
% cat > test.rb
print "hello world\n"
^D
% cat test.rb
print "hello world\n"
% ruby test.rb
hello world |
^D is control-D. The above is just for UNIX. If you're using
DOS, try this:
C:\ruby> copy con: test.rb
print "hello world\n"
^Z
C:\ruby> type test.rb
print "hello world\n"
C:\ruby> ruby test.rb
hello world |
When writing more substantial code than this, you will want to use
a real text editor!
Some surprisingly complex and useful things can be done with
miniature programs that fit in a command line. For example, this
one replaces foo with bar in all C source
and header files in the current working directory, backing up the
original files with ".bak" appended:
% ruby -i.bak -pe 'sub "foo", "bar"' *.[ch] |
This program works like the UNIX cat command (but works
slower than cat):
