1#
2# For a description of the syntax of this configuration file,
3# see scripts/kbuild/config-language.txt.
4#
5
6menu "Shells"
7
8INSERT
9
10config ASH
11	bool "ash"
12	default y
13	depends on !NOMMU
14	help
15	  Tha 'ash' shell adds about 60k in the default configuration and is
16	  the most complete and most pedantically correct shell included with
17	  busybox. This shell is actually a derivative of the Debian 'dash'
18	  shell (by Herbert Xu), which was created by porting the 'ash' shell
19	  (written by Kenneth Almquist) from NetBSD.
20
21config ASH_BASH_COMPAT
22	bool "bash-compatible extensions"
23	default y
24	depends on ASH
25	help
26	  Enable bash-compatible extensions.
27
28config ASH_JOB_CONTROL
29	bool "Job control"
30	default y
31	depends on ASH
32	help
33	  Enable job control in the ash shell.
34
35config ASH_ALIAS
36	bool "alias support"
37	default y
38	depends on ASH
39	help
40	  Enable alias support in the ash shell.
41
42config ASH_GETOPTS
43	bool "Builtin getopt to parse positional parameters"
44	default y
45	depends on ASH
46	help
47	  Enable getopts builtin in the ash shell.
48
49config ASH_BUILTIN_ECHO
50	bool "Builtin version of 'echo'"
51	default y
52	depends on ASH
53	help
54	  Enable support for echo, builtin to ash.
55
56config ASH_BUILTIN_PRINTF
57	bool "Builtin version of 'printf'"
58	default y
59	depends on ASH
60	help
61	  Enable support for printf, builtin to ash.
62
63config ASH_BUILTIN_TEST
64	bool "Builtin version of 'test'"
65	default y
66	depends on ASH
67	help
68	  Enable support for test, builtin to ash.
69
70config ASH_CMDCMD
71	bool "'command' command to override shell builtins"
72	default y
73	depends on ASH
74	help
75	  Enable support for the ash 'command' builtin, which allows
76	  you to run the specified command with the specified arguments,
77	  even when there is an ash builtin command with the same name.
78
79config ASH_MAIL
80	bool "Check for new mail on interactive shells"
81	default n
82	depends on ASH
83	help
84	  Enable "check for new mail" in the ash shell.
85
86config ASH_OPTIMIZE_FOR_SIZE
87	bool "Optimize for size instead of speed"
88	default y
89	depends on ASH
90	help
91	  Compile ash for reduced size at the price of speed.
92
93config ASH_RANDOM_SUPPORT
94	bool "Pseudorandom generator and $RANDOM variable"
95	default y
96	depends on ASH
97	help
98	  Enable pseudorandom generator and dynamic variable "$RANDOM".
99	  Each read of "$RANDOM" will generate a new pseudorandom value.
100	  You can reset the generator by using a specified start value.
101	  After "unset RANDOM" the generator will switch off and this
102	  variable will no longer have special treatment.
103
104config ASH_EXPAND_PRMT
105	bool "Expand prompt string"
106	default y
107	depends on ASH
108	help
109	  "PS#" may contain volatile content, such as backquote commands.
110	  This option recreates the prompt string from the environment
111	  variable each time it is displayed.
112
113config HUSH
114	bool "hush"
115	default y
116	help
117	  hush is a small shell (22k). It handles the normal flow control
118	  constructs such as if/then/elif/else/fi, for/in/do/done, while loops,
119	  case/esac. Redirections, here documents, $((arithmetic))
120	  and functions are supported.
121
122	  It will compile and work on no-mmu systems.
123
124	  It does not handle select, aliases, brace expansion,
125	  tilde expansion, &>file and >&file redirection of stdout+stderr.
126
127config HUSH_BASH_COMPAT
128	bool "bash-compatible extensions"
129	default y
130	depends on HUSH
131	help
132	  Enable bash-compatible extensions.
133
134config HUSH_HELP
135	bool "help builtin"
136	default y
137	depends on HUSH
138	help
139	  Enable help builtin in hush. Code size + ~1 kbyte.
140
141config HUSH_INTERACTIVE
142	bool "Interactive mode"
143	default y
144	depends on HUSH
145	help
146	  Enable interactive mode (prompt and command editing).
147	  Without this, hush simply reads and executes commands
148	  from stdin just like a shell script from a file.
149	  No prompt, no PS1/PS2 magic shell variables.
150
151config HUSH_JOB
152	bool "Job control"
153	default y
154	depends on HUSH_INTERACTIVE
155	help
156	  Enable job control: Ctrl-Z backgrounds, Ctrl-C interrupts current
157	  command (not entire shell), fg/bg builtins work. Without this option,
158	  "cmd &" still works by simply spawning a process and immediately
159	  prompting for next command (or executing next command in a script),
160	  but no separate process group is formed.
161
162config HUSH_TICK
163	bool "Process substitution"
164	default y
165	depends on HUSH
166	help
167	  Enable process substitution `command` and $(command) in hush.
168
169config HUSH_IF
170	bool "Support if/then/elif/else/fi"
171	default y
172	depends on HUSH
173	help
174	  Enable if/then/elif/else/fi in hush.
175
176config HUSH_LOOPS
177	bool "Support for, while and until loops"
178	default y
179	depends on HUSH
180	help
181	  Enable for, while and until loops in hush.
182
183config HUSH_CASE
184	bool "Support case ... esac statement"
185	default y
186	depends on HUSH
187	help
188	  Enable case ... esac statement in hush. +400 bytes.
189
190config HUSH_FUNCTIONS
191	bool "Support funcname() { commands; } syntax"
192	default y
193	depends on HUSH
194	help
195	  Enable support for shell functions in hush. +800 bytes.
196
197config HUSH_LOCAL
198	bool "Support local builtin"
199	default y
200	depends on HUSH_FUNCTIONS
201	help
202	  Enable support for local variables in functions.
203
204config HUSH_EXPORT_N
205	bool "Support export '-n' option"
206	default y
207	depends on HUSH
208	help
209	  Enable support for export '-n' option in hush. It is a bash extension.
210
211config HUSH_RANDOM_SUPPORT
212	bool "Pseudorandom generator and $RANDOM variable"
213	default y
214	depends on HUSH
215	help
216	  Enable pseudorandom generator and dynamic variable "$RANDOM".
217	  Each read of "$RANDOM" will generate a new pseudorandom value.
218
219
220choice
221	prompt "Choose which shell is aliased to 'sh' name"
222	default FEATURE_SH_IS_ASH
223	help
224	  Choose which shell you want to be executed by 'sh' alias.
225	  The ash shell is the most bash compatible and full featured one.
226
227# note: cannot use "select ASH" here, it breaks "make allnoconfig"
228config FEATURE_SH_IS_ASH
229	depends on ASH
230	bool "ash"
231	depends on !NOMMU
232
233config FEATURE_SH_IS_HUSH
234	depends on HUSH
235	bool "hush"
236
237config FEATURE_SH_IS_NONE
238	bool "none"
239
240endchoice
241
242choice
243	prompt "Choose which shell is aliased to 'bash' name"
244	default FEATURE_BASH_IS_NONE
245	help
246	  Choose which shell you want to be executed by 'bash' alias.
247	  The ash shell is the most bash compatible and full featured one.
248
249	  Note that selecting this option does not switch on any bash
250	  compatibility code. It merely makes it possible to install
251	  /bin/bash (sym)link and run scripts which start with
252	  #!/bin/bash line.
253
254	  Many systems use it in scripts which use bash-specific features,
255	  even simple ones like $RANDOM. Without this option, busybox
256	  can't be used for running them because it won't recongnize
257	  "bash" as a supported applet name.
258
259config FEATURE_BASH_IS_ASH
260	depends on ASH
261	bool "ash"
262	depends on !NOMMU
263
264config FEATURE_BASH_IS_HUSH
265	depends on HUSH
266	bool "hush"
267
268config FEATURE_BASH_IS_NONE
269	bool "none"
270
271endchoice
272
273
274config LASH
275	bool "lash (deprecated: aliased to hush)"
276	default n
277	select HUSH
278	help
279	  lash is deprecated and will be removed, please migrate to hush.
280
281config MSH
282	bool "msh (deprecated: please use hush)"
283	default n
284	select HUSH
285	help
286	  msh is deprecated and will be removed, please migrate to hush.
287	  If there is a feature msh has but hush does not, please let us know.
288
289#	  The minix shell (adds just 30k) is quite complete and handles things
290#	  like for/do/done, case/esac and all the things you expect a Bourne
291#	  shell to do. It is not always pedantically correct about Bourne
292#	  shell grammar (try running the shell testscript "tests/sh.testcases"
293#	  on it and compare vs bash) but for most things it works quite well.
294#	  It uses only vfork, so it can be used on uClinux systems.
295
296
297config SH_MATH_SUPPORT
298	bool "POSIX math support"
299	default y
300	depends on ASH || HUSH
301	help
302	  Enable math support in the shell via $((...)) syntax.
303
304config SH_MATH_SUPPORT_64
305	bool "Extend POSIX math support to 64 bit"
306	default y
307	depends on SH_MATH_SUPPORT
308	help
309	  Enable 64-bit math support in the shell. This will make the shell
310	  slightly larger, but will allow computation with very large numbers.
311	  This is not in POSIX, so do not rely on this in portable code.
312
313config FEATURE_SH_EXTRA_QUIET
314	bool "Hide message on interactive shell startup"
315	default y
316	depends on HUSH || ASH
317	help
318	  Remove the busybox introduction when starting a shell.
319
320config FEATURE_SH_STANDALONE
321	bool "Standalone shell"
322	default n
323	depends on (HUSH || ASH) && FEATURE_PREFER_APPLETS
324	help
325	  This option causes busybox shells to use busybox applets
326	  in preference to executables in the PATH whenever possible. For
327	  example, entering the command 'ifconfig' into the shell would cause
328	  busybox to use the ifconfig busybox applet. Specifying the fully
329	  qualified executable name, such as '/sbin/ifconfig' will still
330	  execute the /sbin/ifconfig executable on the filesystem. This option
331	  is generally used when creating a statically linked version of busybox
332	  for use as a rescue shell, in the event that you screw up your system.
333
334	  This is implemented by re-execing /proc/self/exe (typically)
335	  with right parameters. Some selected applets ("NOFORK" applets)
336	  can even be executed without creating new process.
337	  Instead, busybox will call <applet>_main() internally.
338
339	  However, this causes problems in chroot jails without mounted /proc
340	  and with ps/top (command name can be shown as 'exe' for applets
341	  started this way).
342# untrue?
343#	  Note that this will *also* cause applets to take precedence
344#	  over shell builtins of the same name. So turning this on will
345#	  eliminate any performance gained by turning on the builtin "echo"
346#	  and "test" commands in ash.
347# untrue?
348#	  Note that when using this option, the shell will attempt to directly
349#	  run '/bin/busybox'. If you do not have the busybox binary sitting in
350#	  that exact location with that exact name, this option will not work at
351#	  all.
352
353config FEATURE_SH_NOFORK
354	bool "Run 'nofork' applets directly"
355	default n
356	depends on (HUSH || ASH) && FEATURE_PREFER_APPLETS
357	help
358	  This option causes busybox shells [currently only ash]
359	  to not execute typical fork/exec/wait sequence, but call <applet>_main
360	  directly, if possible. (Sometimes it is not possible: for example,
361	  this is not possible in pipes).
362
363	  This will be done only for some applets (those which are marked
364	  NOFORK in include/applets.h).
365
366	  This may significantly speed up some shell scripts.
367
368	  This feature is relatively new. Use with care.
369
370config CTTYHACK
371	bool "cttyhack"
372	default y
373	help
374	  One common problem reported on the mailing list is "can't access tty;
375	  job control turned off" error message which typically appears when
376	  one tries to use shell with stdin/stdout opened to /dev/console.
377	  This device is special - it cannot be a controlling tty.
378
379	  Proper solution is to use correct device instead of /dev/console.
380
381	  cttyhack provides "quick and dirty" solution to this problem.
382	  It analyzes stdin with various ioctls, trying to determine whether
383	  it is a /dev/ttyN or /dev/ttySN (virtual terminal or serial line).
384	  If it detects one, it closes stdin/out/err and reopens that device.
385	  Then it executes given program. Opening the device will make
386	  that device a controlling tty. This may require cttyhack
387	  to be a session leader.
388
389	  Example for /etc/inittab (for busybox init):
390
391	  ::respawn:/bin/cttyhack /bin/sh
392
393	  Giving controlling tty to shell running with PID 1:
394
395	  $ exec cttyhack sh
396
397	  Starting an interactive shell from boot shell script:
398
399	  setsid cttyhack sh
400
401endmenu
402