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 "lash (deprecated: aliased to hush)"
240 lash is deprecated and will be removed, please migrate to hush.
243 bool "msh (deprecated: please use hush)"
246 msh is deprecated and will be removed, please migrate to hush.
247 If there is a feature msh has but hush does not, please let us know.
249 # The minix shell (adds just 30k) is quite complete and handles things
250 # like for/do/done, case/esac and all the things you expect a Bourne
251 # shell to do. It is not always pedantically correct about Bourne
252 # shell grammar (try running the shell testscript "tests/sh.testcases"
253 # on it and compare vs bash) but for most things it works quite well.
254 # It uses only vfork, so it can be used on uClinux systems.
257 comment "Bourne Shell Options"
258 depends on MSH || LASH || HUSH || ASH
260 config SH_MATH_SUPPORT
261 bool "POSIX math support"
263 depends on ASH || HUSH
265 Enable math support in the shell via $((...)) syntax.
267 config SH_MATH_SUPPORT_64
268 bool "Extend POSIX math support to 64 bit"
270 depends on SH_MATH_SUPPORT
272 Enable 64-bit math support in the shell. This will make the shell
273 slightly larger, but will allow computation with very large numbers.
274 This is not in POSIX, so do not rely on this in portable code.
276 config FEATURE_SH_EXTRA_QUIET
277 bool "Hide message on interactive shell startup"
279 depends on MSH || LASH || HUSH || ASH
281 Remove the busybox introduction when starting a shell.
283 config FEATURE_SH_STANDALONE
284 bool "Standalone shell"
286 depends on (MSH || LASH || HUSH || ASH) && FEATURE_PREFER_APPLETS
288 This option causes busybox shells to use busybox applets
289 in preference to executables in the PATH whenever possible. For
290 example, entering the command 'ifconfig' into the shell would cause
291 busybox to use the ifconfig busybox applet. Specifying the fully
292 qualified executable name, such as '/sbin/ifconfig' will still
293 execute the /sbin/ifconfig executable on the filesystem. This option
294 is generally used when creating a statically linked version of busybox
295 for use as a rescue shell, in the event that you screw up your system.
297 This is implemented by re-execing /proc/self/exe (typically)
298 with right parameters. Some selected applets ("NOFORK" applets)
299 can even be executed without creating new process.
300 Instead, busybox will call <applet>_main() internally.
302 However, this causes problems in chroot jails without mounted /proc
303 and with ps/top (command name can be shown as 'exe' for applets
306 # Note that this will *also* cause applets to take precedence
307 # over shell builtins of the same name. So turning this on will
308 # eliminate any performance gained by turning on the builtin "echo"
309 # and "test" commands in ash.
311 # Note that when using this option, the shell will attempt to directly
312 # run '/bin/busybox'. If you do not have the busybox binary sitting in
313 # that exact location with that exact name, this option will not work at
316 config FEATURE_SH_NOFORK
317 bool "Run 'nofork' applets directly"
319 depends on (MSH || LASH || HUSH || ASH) && FEATURE_PREFER_APPLETS
321 This option causes busybox shells [currently only ash]
322 to not execute typical fork/exec/wait sequence, but call <applet>_main
323 directly, if possible. (Sometimes it is not possible: for example,
324 this is not possible in pipes).
326 This will be done only for some applets (those which are marked
327 NOFORK in include/applets.h).
329 This may significantly speed up some shell scripts.
331 This feature is relatively new. Use with care.
337 One common problem reported on the mailing list is "can't access tty;
338 job control turned off" error message which typically appears when
339 one tries to use shell with stdin/stdout opened to /dev/console.
340 This device is special - it cannot be a controlling tty.
342 Proper solution is to use correct device instead of /dev/console.
344 cttyhack provides "quick and dirty" solution to this problem.
345 It analyzes stdin with various ioctls, trying to determine whether
346 it is a /dev/ttyN or /dev/ttySN (virtual terminal or serial line).
347 If it detects one, it closes stdin/out/err and reopens that device.
348 Then it executes given program. Usage example for /etc/inittab
351 ::respawn:/bin/cttyhack /bin/sh