End of Life Ruby 3.0 has reached end of life and gets no more fixes. Switch to Ruby 4.0 →
instance method
IO#lineno
ios.lineno → integer
io.c
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static VALUE
rb_io_lineno(VALUE io)
{
rb_io_t *fptr;
GetOpenFile(io, fptr);
rb_io_check_char_readable(fptr);
return INT2NUM(fptr->lineno);
}
Returns the current line number in ios. The stream must be opened for reading. lineno counts the number of times gets is called rather than the number of newlines encountered. The two values will differ if gets is called with a separator other than newline.
Methods that use $/ like each, lines and readline will also increment lineno.
See also the $. variable.
Example
f = File.new("testfile") f.lineno #=> 0 f.gets #=> "This is line one\n" f.lineno #=> 1 f.gets #=> "This is line two\n" f.lineno #=> 2