Info Catalog bash: Controlling the Prompt bash: Bash Features bash: Bash POSIX Mode

bash: The Restricted Shell

 
 6.10 The Restricted Shell
 =========================
 
 If Bash is started with the name 'rbash', or the '--restricted' or '-r'
 option is supplied at invocation, the shell becomes restricted.  A
 restricted shell is used to set up an environment more controlled than
 the standard shell.  A restricted shell behaves identically to 'bash'
 with the exception that the following are disallowed or not performed:
 
    * Changing directories with the 'cd' builtin.
    * Setting or unsetting the values of the 'SHELL', 'PATH', 'ENV', or
      'BASH_ENV' variables.
    * Specifying command names containing slashes.
    * Specifying a filename containing a slash as an argument to the '.'
      builtin command.
    * Specifying a filename containing a slash as an argument to the '-p'
      option to the 'hash' builtin command.
    * Importing function definitions from the shell environment at
      startup.
    * Parsing the value of 'SHELLOPTS' from the shell environment at
      startup.
    * Redirecting output using the '>', '>|', '<>', '>&', '&>', and '>>'
      redirection operators.
    * Using the 'exec' builtin to replace the shell with another command.
    * Adding or deleting builtin commands with the '-f' and '-d' options
      to the 'enable' builtin.
    * Using the 'enable' builtin command to enable disabled shell
      builtins.
    * Specifying the '-p' option to the 'command' builtin.
    * Turning off restricted mode with 'set +r' or 'set +o restricted'.
 
    These restrictions are enforced after any startup files are read.
 
    When a command that is found to be a shell script is executed (
 Shell Scripts), 'rbash' turns off any restrictions in the shell
 spawned to execute the script.
 

Info Catalog bash: Controlling the Prompt bash: Bash Features bash: Bash POSIX Mode