Class

Shell implements an idiomatic Ruby interface for common UNIX shell commands.

It provides users the ability to execute commands with filters and pipes, like sh/csh by using native facilities of Ruby.

Examples

Temp file creation

In this example we will create three tmpFile‘s in three different folders under the /tmp directory.

sh = Shell.cd("/tmp") # Change to the /tmp directory
sh.mkdir "shell-test-1" unless sh.exists?("shell-test-1")
# make the 'shell-test-1' directory if it doesn't already exist
sh.cd("shell-test-1") # Change to the /tmp/shell-test-1 directory
for dir in ["dir1", "dir3", "dir5"]
  if !sh.exists?(dir)
    sh.mkdir dir # make dir if it doesn't already exist
    sh.cd(dir) do
      # change to the `dir` directory
      f = sh.open("tmpFile", "w") # open a new file in write mode
      f.print "TEST\n"            # write to the file
      f.close                     # close the file handler
    end
    print sh.pwd                  # output the process working directory
  end
end

Temp file creation with self

This example is identical to the first, except we’re using CommandProcessor#transact.

CommandProcessor#transact executes the given block against self, in this case sh; our Shell object. Within the block we can substitute sh.cd to cd, because the scope within the block uses sh already.

sh = Shell.cd("/tmp")
sh.transact do
  mkdir "shell-test-1" unless exists?("shell-test-1")
  cd("shell-test-1")
  for dir in ["dir1", "dir3", "dir5"]
    if !exists?(dir)
      mkdir dir
      cd(dir) do
        f = open("tmpFile", "w")
        f.print "TEST\n"
        f.close
      end
      print pwd
    end
  end
end

Pipe /etc/printcap into a file

In this example we will read the operating system file /etc/printcap, generated by cupsd, and then output it to a new file relative to the pwd of sh.

sh = Shell.new
sh.cat("/etc/printcap") | sh.tee("tee1") > "tee2"
(sh.cat < "/etc/printcap") | sh.tee("tee11") > "tee12"
sh.cat("/etc/printcap") | sh.tee("tee1") >> "tee2"
(sh.cat < "/etc/printcap") | sh.tee("tee11") >> "tee12"
Attributes
Read & Write
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Read & Write
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Returns the command search path in an array

Read & Write

Returns the umask

Read & Write
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Read
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Read & Write
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Read
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cwd

Read

Returns the current working directory.

dir

Read

Returns the current working directory.

Read

Returns the current working directory.

pwd

Read

Returns the current working directory.

Read
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Read
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Class Methods

Convenience method for Shell::CommandProcessor.alias_command. Defines an instance method which will execute a command under an alternative name.

Shell.def_system_command('date')
Shell.alias_command('date_in_utc', 'date', '-u')
Shell.new.date_in_utc # => Sat Jan 25 16:59:57 UTC 2014

Creates a new Shell instance with the current working directory set to path.

No documentation available

Convenience method for Shell::CommandProcessor.def_system_command. Defines an instance method which will execute the given shell command. If the executable is not in Shell.default_system_path, you must supply the path to it.

Shell.def_system_command('hostname')
Shell.new.hostname # => localhost

# How to use an executable that's not in the default path

Shell.def_system_command('run_my_program', "~/hello")
Shell.new.run_my_program # prints "Hello from a C program!"
No documentation available
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Returns the directories in the current shell’s PATH environment variable as an array of directory names. This sets the system_path for all instances of Shell.

Example: If in your current shell, you did:

$ echo $PATH
/usr/bin:/bin:/usr/local/bin

Running this method in the above shell would then return:

["/usr/bin", "/bin", "/usr/local/bin"]

Sets the system_path that new instances of Shell should have as their initial system_path.

path should be an array of directory name strings.

Convenience method for Shell::CommandProcessor.install_system_commands. Defines instance methods representing all the executable files found in Shell.default_system_path, with the given prefix prepended to their names.

Shell.install_system_commands
Shell.new.sys_echo("hello") # => hello

Creates a Shell object which current directory is set to the process current directory, unless otherwise specified by the pwd argument.

No documentation available
Instance Methods

Creates a Shell object which current directory is set to path.

If a block is given, it restores the current directory when the block ends.

If called as iterator, it restores the current directory when the block ends.

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Returns a list of scheduled jobs.

Sends the given signal to the given job

An alias for popdir

Pops a directory from the directory stack, and sets the current directory to it.

Pushes the current directory to the directory stack, changing the current directory to path.

If path is omitted, it exchanges its current directory and the top of its directory stack.

If a block is given, it restores the current directory when the block ends.

Sets the system path (the Shell instance’s PATH environment variable).

path should be an array of directory name strings.