| 1 | 6.10 The Restricted Shell
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| 2 | =========================
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| 3 |
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| 4 | If Bash is started with the name `rbash', or the `--restricted' or `-r'
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| 5 | option is supplied at invocation, the shell becomes restricted. A
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| 6 | restricted shell is used to set up an environment more controlled than
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| 7 | the standard shell. A restricted shell behaves identically to `bash'
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| 8 | with the exception that the following are disallowed or not performed:
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| 9 |
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| 10 | * Changing directories with the `cd' builtin.
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| 11 |
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| 12 | * Setting or unsetting the values of the `SHELL', `PATH', `ENV', or
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| 13 | `BASH_ENV' variables.
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| 14 |
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| 15 | * Specifying command names containing slashes.
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| 16 |
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| 17 | * Specifying a filename containing a slash as an argument to the `.'
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| 18 | builtin command.
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| 19 |
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| 20 | * Specifying a filename containing a slash as an argument to the `-p'
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| 21 | option to the `hash' builtin command.
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| 22 |
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| 23 | * Importing function definitions from the shell environment at
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| 24 | startup.
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| 25 |
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| 26 | * Parsing the value of `SHELLOPTS' from the shell environment at
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| 27 | startup.
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| 28 |
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| 29 | * Redirecting output using the `>', `>|', `<>', `>&', `&>', and `>>'
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| 30 | redirection operators.
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| 31 |
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| 32 | * Using the `exec' builtin to replace the shell with another command.
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| 33 |
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| 34 | * Adding or deleting builtin commands with the `-f' and `-d' options
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| 35 | to the `enable' builtin.
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| 36 |
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| 37 | * Using the `enable' builtin command to enable disabled shell
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| 38 | builtins.
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| 39 |
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| 40 | * Specifying the `-p' option to the `command' builtin.
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| 41 |
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| 42 | * Turning off restricted mode with `set +r' or `set +o restricted'.
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| 43 |
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| 44 | These restrictions are enforced after any startup files are read.
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| 45 |
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| 46 | When a command that is found to be a shell script is executed (*note
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| 47 | Shell Scripts::), `rbash' turns off any restrictions in the shell
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| 48 | spawned to execute the script.
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| 49 |
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