2 # For a description of the syntax of this configuration file,
3 # see scripts/kbuild/config-language.txt.
9 prompt "Choose your default shell"
10 default FEATURE_SH_IS_NONE
12 Choose a shell. The ash shell is the most bash compatible
13 and full featured one.
15 config FEATURE_SH_IS_ASH
20 config FEATURE_SH_IS_HUSH
24 ####config FEATURE_SH_IS_LASH
28 ####config FEATURE_SH_IS_MSH
32 config FEATURE_SH_IS_NONE
42 Tha 'ash' shell adds about 60k in the default configuration and is
43 the most complete and most pedantically correct shell included with
44 busybox. This shell is actually a derivative of the Debian 'dash'
45 shell (by Herbert Xu), which was created by porting the 'ash' shell
46 (written by Kenneth Almquist) from NetBSD.
48 config ASH_BASH_COMPAT
49 bool "bash-compatible extensions"
53 Enable bash-compatible extensions.
55 config ASH_JOB_CONTROL
60 Enable job control in the ash shell.
67 Enable alias support in the ash shell.
70 bool "Builtin getopt to parse positional parameters"
74 Enable getopts builtin in the ash shell.
76 config ASH_BUILTIN_ECHO
77 bool "Builtin version of 'echo'"
81 Enable support for echo, builtin to ash.
83 config ASH_BUILTIN_PRINTF
84 bool "Builtin version of 'printf'"
88 Enable support for printf, builtin to ash.
90 config ASH_BUILTIN_TEST
91 bool "Builtin version of 'test'"
95 Enable support for test, builtin to ash.
98 bool "'command' command to override shell builtins"
102 Enable support for the ash 'command' builtin, which allows
103 you to run the specified command with the specified arguments,
104 even when there is an ash builtin command with the same name.
107 bool "Check for new mail on interactive shells"
111 Enable "check for new mail" in the ash shell.
113 config ASH_OPTIMIZE_FOR_SIZE
114 bool "Optimize for size instead of speed"
118 Compile ash for reduced size at the price of speed.
120 config ASH_RANDOM_SUPPORT
121 bool "Pseudorandom generator and $RANDOM variable"
125 Enable pseudorandom generator and dynamic variable "$RANDOM".
126 Each read of "$RANDOM" will generate a new pseudorandom value.
127 You can reset the generator by using a specified start value.
128 After "unset RANDOM" the generator will switch off and this
129 variable will no longer have special treatment.
131 config ASH_EXPAND_PRMT
132 bool "Expand prompt string"
136 "PS#" may contain volatile content, such as backquote commands.
137 This option recreates the prompt string from the environment
138 variable each time it is displayed.
144 hush is a small shell (22k). It handles the normal flow control
145 constructs such as if/then/elif/else/fi, for/in/do/done, while loops,
146 case/esac. Redirections, here documents, $((arithmetic))
147 and functions are supported.
149 It will compile and work on no-mmu systems.
151 It does not handle select, aliases, brace expansion,
152 tilde expansion, &>file and >&file redirection of stdout+stderr.
154 config HUSH_BASH_COMPAT
155 bool "bash-compatible extensions"
159 Enable bash-compatible extensions.
166 Enable help builtin in hush. Code size + ~1 kbyte.
168 config HUSH_INTERACTIVE
169 bool "Interactive mode"
173 Enable interactive mode (prompt and command editing).
174 Without this, hush simply reads and executes commands
175 from stdin just like a shell script from a file.
176 No prompt, no PS1/PS2 magic shell variables.
181 depends on HUSH_INTERACTIVE
183 Enable job control: Ctrl-Z backgrounds, Ctrl-C interrupts current
184 command (not entire shell), fg/bg builtins work. Without this option,
185 "cmd &" still works by simply spawning a process and immediately
186 prompting for next command (or executing next command in a script),
187 but no separate process group is formed.
190 bool "Process substitution"
194 Enable process substitution `command` and $(command) in hush.
197 bool "Support if/then/elif/else/fi"
201 Enable if/then/elif/else/fi in hush.
204 bool "Support for, while and until loops"
208 Enable for, while and until loops in hush.
211 bool "Support case ... esac statement"
215 Enable case ... esac statement in hush. +400 bytes.
217 config HUSH_FUNCTIONS
218 bool "Support funcname() { commands; } syntax"
222 Enable support for shell functions in hush. +800 bytes.
225 bool "Support local builtin"
227 depends on HUSH_FUNCTIONS
229 Enable support for local variables in functions.
232 bool "Support export '-n' option"
236 Enable support for export '-n' option in hush. It is a bash extension.
238 config HUSH_RANDOM_SUPPORT
239 bool "Pseudorandom generator and $RANDOM variable"
243 Enable pseudorandom generator and dynamic variable "$RANDOM".
244 Each read of "$RANDOM" will generate a new pseudorandom value.
247 bool "lash (deprecated: aliased to hush)"
251 lash is deprecated and will be removed, please migrate to hush.
254 bool "msh (deprecated: please use hush)"
258 msh is deprecated and will be removed, please migrate to hush.
259 If there is a feature msh has but hush does not, please let us know.
261 # The minix shell (adds just 30k) is quite complete and handles things
262 # like for/do/done, case/esac and all the things you expect a Bourne
263 # shell to do. It is not always pedantically correct about Bourne
264 # shell grammar (try running the shell testscript "tests/sh.testcases"
265 # on it and compare vs bash) but for most things it works quite well.
266 # It uses only vfork, so it can be used on uClinux systems.
269 config SH_MATH_SUPPORT
270 bool "POSIX math support"
272 depends on ASH || HUSH
274 Enable math support in the shell via $((...)) syntax.
276 config SH_MATH_SUPPORT_64
277 bool "Extend POSIX math support to 64 bit"
279 depends on SH_MATH_SUPPORT
281 Enable 64-bit math support in the shell. This will make the shell
282 slightly larger, but will allow computation with very large numbers.
283 This is not in POSIX, so do not rely on this in portable code.
285 config FEATURE_SH_EXTRA_QUIET
286 bool "Hide message on interactive shell startup"
288 depends on MSH || LASH || HUSH || ASH
290 Remove the busybox introduction when starting a shell.
292 config FEATURE_SH_STANDALONE
293 bool "Standalone shell"
295 depends on (MSH || LASH || HUSH || ASH) && FEATURE_PREFER_APPLETS
297 This option causes busybox shells to use busybox applets
298 in preference to executables in the PATH whenever possible. For
299 example, entering the command 'ifconfig' into the shell would cause
300 busybox to use the ifconfig busybox applet. Specifying the fully
301 qualified executable name, such as '/sbin/ifconfig' will still
302 execute the /sbin/ifconfig executable on the filesystem. This option
303 is generally used when creating a statically linked version of busybox
304 for use as a rescue shell, in the event that you screw up your system.
306 This is implemented by re-execing /proc/self/exe (typically)
307 with right parameters. Some selected applets ("NOFORK" applets)
308 can even be executed without creating new process.
309 Instead, busybox will call <applet>_main() internally.
311 However, this causes problems in chroot jails without mounted /proc
312 and with ps/top (command name can be shown as 'exe' for applets
315 # Note that this will *also* cause applets to take precedence
316 # over shell builtins of the same name. So turning this on will
317 # eliminate any performance gained by turning on the builtin "echo"
318 # and "test" commands in ash.
320 # Note that when using this option, the shell will attempt to directly
321 # run '/bin/busybox'. If you do not have the busybox binary sitting in
322 # that exact location with that exact name, this option will not work at
325 config FEATURE_SH_NOFORK
326 bool "Run 'nofork' applets directly"
328 depends on (MSH || LASH || HUSH || ASH) && FEATURE_PREFER_APPLETS
330 This option causes busybox shells [currently only ash]
331 to not execute typical fork/exec/wait sequence, but call <applet>_main
332 directly, if possible. (Sometimes it is not possible: for example,
333 this is not possible in pipes).
335 This will be done only for some applets (those which are marked
336 NOFORK in include/applets.h).
338 This may significantly speed up some shell scripts.
340 This feature is relatively new. Use with care.
346 One common problem reported on the mailing list is "can't access tty;
347 job control turned off" error message which typically appears when
348 one tries to use shell with stdin/stdout opened to /dev/console.
349 This device is special - it cannot be a controlling tty.
351 Proper solution is to use correct device instead of /dev/console.
353 cttyhack provides "quick and dirty" solution to this problem.
354 It analyzes stdin with various ioctls, trying to determine whether
355 it is a /dev/ttyN or /dev/ttySN (virtual terminal or serial line).
356 If it detects one, it closes stdin/out/err and reopens that device.
357 Then it executes given program. Usage example for /etc/inittab
360 ::respawn:/bin/cttyhack /bin/sh