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
19 config FEATURE_SH_IS_HUSH
23 ####config FEATURE_SH_IS_LASH
27 config FEATURE_SH_IS_MSH
31 config FEATURE_SH_IS_NONE
40 Tha 'ash' shell adds about 60k in the default configuration and is
41 the most complete and most pedantically correct shell included with
42 busybox. This shell is actually a derivative of the Debian 'dash'
43 shell (by Herbert Xu), which was created by porting the 'ash' shell
44 (written by Kenneth Almquist) from NetBSD.
46 comment "Ash Shell Options"
49 config ASH_BASH_COMPAT
50 bool "bash-compatible extensions"
54 Enable bash-compatible extensions.
56 config ASH_JOB_CONTROL
61 Enable job control in the ash shell.
63 config ASH_READ_NCHARS
64 bool "'read -n N' and 'read -s' support"
68 'read -n N' will return a value after N characters have been read.
69 'read -s' will read without echoing the user's input.
71 config ASH_READ_TIMEOUT
72 bool "'read -t S' support"
76 'read -t S' will return a value after S seconds have passed.
77 This implementation will allow fractional seconds, expressed
78 as a decimal fraction, e.g. 'read -t 2.5 foo'.
85 Enable alias support in the ash shell.
88 bool "Builtin getopt to parse positional parameters"
92 Enable getopts builtin in the ash shell.
94 config ASH_BUILTIN_ECHO
95 bool "Builtin version of 'echo'"
99 Enable support for echo, builtin to ash.
101 config ASH_BUILTIN_PRINTF
102 bool "Builtin version of 'printf'"
106 Enable support for printf, builtin to ash.
108 config ASH_BUILTIN_TEST
109 bool "Builtin version of 'test'"
113 Enable support for test, builtin to ash.
116 bool "'command' command to override shell builtins"
120 Enable support for the ash 'command' builtin, which allows
121 you to run the specified command with the specified arguments,
122 even when there is an ash builtin command with the same name.
125 bool "Check for new mail on interactive shells"
129 Enable "check for new mail" in the ash shell.
131 config ASH_OPTIMIZE_FOR_SIZE
132 bool "Optimize for size instead of speed"
136 Compile ash for reduced size at the price of speed.
138 config ASH_RANDOM_SUPPORT
139 bool "Pseudorandom generator and $RANDOM variable"
143 Enable pseudorandom generator and dynamic variable "$RANDOM".
144 Each read of "$RANDOM" will generate a new pseudorandom value.
145 You can reset the generator by using a specified start value.
146 After "unset RANDOM" the generator will switch off and this
147 variable will no longer have special treatment.
149 config ASH_EXPAND_PRMT
150 bool "Expand prompt string"
154 "PS#" may contain volatile content, such as backquote commands.
155 This option recreates the prompt string from the environment
156 variable each time it is displayed.
162 hush is a small shell (22k). It handles the normal flow control
163 constructs such as if/then/elif/else/fi, for/in/do/done, while loops,
164 case/esac. Redirections, here documents, $((arithmetic))
165 and functions are supported.
167 It will compile and work on no-mmu systems.
169 It does not handle select, aliases, brace expansion,
170 tilde expansion, &>file and >&file redirection of stdout+stderr.
177 Enable help builtin in hush. Code size + ~1 kbyte.
179 config HUSH_INTERACTIVE
180 bool "Interactive mode"
184 Enable interactive mode (prompt and command editing).
185 Without this, hush simply reads and executes commands
186 from stdin just like a shell script from the file.
187 No prompt, no PS1/PS2 magic shell variables.
192 depends on HUSH_INTERACTIVE
194 Enable job control: Ctrl-Z backgrounds, Ctrl-C interrupts current
195 command (not entire shell), fg/bg builtins work. Without this option,
196 "cmd &" still works by simply spawning a process and immediately
197 prompting for next command (or executing next command in a script),
198 but no separate process group is formed.
201 bool "Process substitution"
205 Enable process substitution `command` and $(command) in hush.
208 bool "Support if/then/elif/else/fi"
212 Enable if/then/elif/else/fi in hush.
215 bool "Support for, while and until loops"
219 Enable for, while and until loops in hush.
222 bool "Support case ... esac statement"
226 Enable case ... esac statement in hush. +400 bytes.
228 config HUSH_FUNCTIONS
229 bool "Support funcname() { commands; } syntax"
233 Enable support for shell functions in hush. +800 bytes.
236 bool "Support local builtin"
238 depends on HUSH_FUNCTIONS
240 Enable support for local variables in functions.
243 bool "Support export '-n' option"
247 Enable support for export '-n' option in hush. It is a bash extension.
250 bool "lash (deprecated: aliased to hush)"
254 lash is deprecated and will be removed, please migrate to hush.
257 bool "msh (deprecated: please use hush)"
260 msh is deprecated and will be removed, please migrate to hush.
261 If there is a feature msh has but hush does not, please let us know.
263 # The minix shell (adds just 30k) is quite complete and handles things
264 # like for/do/done, case/esac and all the things you expect a Bourne
265 # shell to do. It is not always pedantically correct about Bourne
266 # shell grammar (try running the shell testscript "tests/sh.testcases"
267 # on it and compare vs bash) but for most things it works quite well.
268 # It uses only vfork, so it can be used on uClinux systems.
271 comment "Bourne Shell Options"
272 depends on MSH || LASH || HUSH || ASH
274 config SH_MATH_SUPPORT
275 bool "POSIX math support"
277 depends on ASH || HUSH
279 Enable math support in the shell via $((...)) syntax.
281 config SH_MATH_SUPPORT_64
282 bool "Extend POSIX math support to 64 bit"
284 depends on SH_MATH_SUPPORT
286 Enable 64-bit math support in the shell. This will make the shell
287 slightly larger, but will allow computation with very large numbers.
288 This is not in POSIX, so do not rely on this in portable code.
290 config FEATURE_SH_EXTRA_QUIET
291 bool "Hide message on interactive shell startup"
293 depends on MSH || LASH || HUSH || ASH
295 Remove the busybox introduction when starting a shell.
297 config FEATURE_SH_STANDALONE
298 bool "Standalone shell"
300 depends on (MSH || LASH || HUSH || ASH) && FEATURE_PREFER_APPLETS
302 This option causes busybox shells to use busybox applets
303 in preference to executables in the PATH whenever possible. For
304 example, entering the command 'ifconfig' into the shell would cause
305 busybox to use the ifconfig busybox applet. Specifying the fully
306 qualified executable name, such as '/sbin/ifconfig' will still
307 execute the /sbin/ifconfig executable on the filesystem. This option
308 is generally used when creating a statically linked version of busybox
309 for use as a rescue shell, in the event that you screw up your system.
311 This is implemented by re-execing /proc/self/exe (typically)
312 with right parameters. Some selected applets ("NOFORK" applets)
313 can even be executed without creating new process.
314 Instead, busybox will call <applet>_main() internally.
316 However, this causes problems in chroot jails without mounted /proc
317 and with ps/top (command name can be shown as 'exe' for applets
320 # Note that this will *also* cause applets to take precedence
321 # over shell builtins of the same name. So turning this on will
322 # eliminate any performance gained by turning on the builtin "echo"
323 # and "test" commands in ash.
325 # Note that when using this option, the shell will attempt to directly
326 # run '/bin/busybox'. If you do not have the busybox binary sitting in
327 # that exact location with that exact name, this option will not work at
330 config FEATURE_SH_NOFORK
331 bool "Run 'nofork' applets directly"
333 depends on (MSH || LASH || HUSH || ASH) && FEATURE_PREFER_APPLETS
335 This option causes busybox shells [currently only ash]
336 to not execute typical fork/exec/wait sequence, but call <applet>_main
337 directly, if possible. (Sometimes it is not possible: for example,
338 this is not possible in pipes).
340 This will be done only for some applets (those which are marked
341 NOFORK in include/applets.h).
343 This may significantly speed up some shell scripts.
345 This feature is relatively new. Use with care.
351 One common problem reported on the mailing list is "can't access tty;
352 job control turned off" error message which typically appears when
353 one tries to use shell with stdin/stdout opened to /dev/console.
354 This device is special - it cannot be a controlling tty.
356 Proper solution is to use correct device instead of /dev/console.
358 cttyhack provides "quick and dirty" solution to this problem.
359 It analyzes stdin with various ioctls, trying to determine whether
360 it is a /dev/ttyN or /dev/ttySN (virtual terminal or serial line).
361 If it detects one, it closes stdin/out/err and reopens that device.
362 Then it executes given program. Usage example for /etc/inittab
365 ::respawn:/bin/cttyhack /bin/sh