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| -rw-r--r-- | doc/command_line/environment.md | 173 |
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diff --git a/doc/command_line/environment.md b/doc/command_line/environment.md deleted file mode 100644 index abdfd5cfeb..0000000000 --- a/doc/command_line/environment.md +++ /dev/null @@ -1,173 +0,0 @@ -## Environment - -Certain command-line options affect the execution environment -of the invoked Ruby program. - -### About the Examples - -The examples here use command-line option `-e`, -which passes the Ruby code to be executed on the command line itself: - -```sh -$ ruby -e 'puts "Hello, World."' -``` - -### Option `-C` - -The argument to option `-C` specifies a working directory -for the invoked Ruby program; -does not change the working directory for the current process: - -```sh -$ basename `pwd` -ruby -$ ruby -C lib -e 'puts File.basename(Dir.pwd)' -lib -$ basename `pwd` -ruby -``` - -Whitespace between the option and its argument may be omitted. - -### Option `-I` - -The argument to option `-I` specifies a directory -to be added to the array in global variable `$LOAD_PATH`; -the option may be given more than once: - -```sh -$ pushd /tmp -$ ruby -e 'p $LOAD_PATH.size' -8 -$ ruby -I my_lib -I some_lib -e 'p $LOAD_PATH.size' -10 -$ ruby -I my_lib -I some_lib -e 'p $LOAD_PATH.take(2)' -["/tmp/my_lib", "/tmp/some_lib"] -$ popd -``` - -Whitespace between the option and its argument may be omitted. - -### Option `-r` - -The argument to option `-r` specifies a library to be required -before executing the Ruby program; -the option may be given more than once: - -```sh -$ ruby -e 'p defined?(JSON); p defined?(CSV)' -nil -nil -$ ruby -r CSV -r JSON -e 'p defined?(JSON); p defined?(CSV)' -"constant" -"constant" -``` - -Whitespace between the option and its argument may be omitted. - -### Option `-0` - -Option `-0` defines the input record separator `$/` -for the invoked Ruby program. - -The optional argument to the option must be octal digits, -each in the range `0..7`; -these digits are prefixed with digit `0` to form an octal value: - -- If no argument is given, the input record separator is `0x00`. -- If the argument is `0`, the input record separator is `''`; - see {Special Line Separator Values}[rdoc-ref:IO@Special+Line+Separator+Values]. -- If the argument is in range `(1..0377)`, - it becomes the character value of the input record separator `$/`. -- Otherwise, the input record separator is `nil`. - -Examples: - -```sh -$ ruby -0 -e 'p $/' -"\x00" -ruby -00 -e 'p $/' -"" -$ ruby -012 -e 'p $/' -"\n" -$ ruby -015 -e 'p $/' -"\r" -$ ruby -0377 -e 'p $/' -"\xFF" -$ ruby -0400 -e 'p $/' -nil -``` - -The option may not be separated from its argument by whitespace. - -### Option `-d` - -Some code in (or called by) the Ruby program may include statements or blocks -conditioned by the global variable `$DEBUG` (e.g., `if $DEBUG`); -these commonly write to `$stdout` or `$stderr`. - -The default value for `$DEBUG` is `false`; -option `-d` (or `--debug`) sets it to `true`: - -```sh -$ ruby -e 'p $DEBUG' -false -$ ruby -d -e 'p $DEBUG' -true -``` - -### Option '-w' - -Option `-w` (lowercase letter) is equivalent to option `-W1` (uppercase letter). - -### Option `-W` - -Any Ruby code can create a <i>warning message</i> by calling method Kernel#warn; -methods in the Ruby core and standard libraries can also create warning messages. -Such a message may be printed on `$stderr` -(or not, depending on certain settings). - -Option `-W` helps determine whether a particular warning message -will be written, -by setting the initial value of global variable `$-W`: - -- `-W0`: Sets `$-W` to `0` (silent; no warnings). -- `-W1`: Sets `$-W` to `1` (moderate verbosity). -- `-W2`: Sets `$-W` to `2` (high verbosity). -- `-W`: Same as `-W2` (high verbosity). -- Option not given: Same as `-W1` (moderate verbosity). - -The value of `$-W`, in turn, determines which warning messages (if any) -are to be printed to `$stdout` (see Kernel#warn): - -```sh -$ ruby -W1 -e 'p $foo' -nil -$ ruby -W2 -e 'p $foo' --e:1: warning: global variable '$foo' not initialized -nil -``` - -Ruby code may also define warnings for certain categories; -these are the default settings for the defined categories: - -``` -Warning[:experimental] # => true -Warning[:deprecated] # => false -Warning[:performance] # => false -``` - -They may also be set: -``` -Warning[:experimental] = false -Warning[:deprecated] = true -Warning[:performance] = true -``` - -You can suppress a category by prefixing `no-` to the category name: - -``` -$ ruby -W:no-experimental -e 'p IO::Buffer.new' -#<IO::Buffer> -``` - |