class method
File.expand_path
(::string | ::_ToPath file_name, ?::string | ::_ToPath dir_string) -> ::String
File.expand_path(file_name [, dir_string] ) → abs_file_name
file.c
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static VALUE
s_expand_path(int c, const VALUE * v, VALUE _)
{
return rb_file_s_expand_path(c, v);
}
Converts a pathname to an absolute pathname. Relative paths are referenced from the current working directory of the process unless dir_string is given, in which case it will be used as the starting point. The given pathname may start with a “~”, which expands to the process owner’s home directory (the environment variable HOME must be set correctly). “~user” expands to the named user’s home directory.
Example
File.expand_path("~oracle/bin") #=> "/home/oracle/bin"
A simple example of using dir_string is as follows.
Example
File.expand_path("ruby", "/usr/bin") #=> "/usr/bin/ruby"
A more complex example which also resolves parent directory is as follows. Suppose we are in bin/mygem and want the absolute path of lib/mygem.rb.
Example
File.expand_path("../../lib/mygem.rb", __FILE__) #=> ".../path/to/project/lib/mygem.rb"
So first it resolves the parent of __FILE__, that is bin/, then go to the parent, the root of the project and appends lib/mygem.rb.