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 variable $RANDOM"
143 Enable pseudorandom generator and dynamic variable "$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" then 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 be 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 very small shell (just 18k) and it has fairly complete
163 Bourne shell grammar. It even handles all the normal flow control
164 options such as if/then/elif/else/fi, for/in/do/done, while loops,
167 It uses only vfork, so it can be used on no-mmu systems.
169 It does not handle select, functions, here documents ( <<
170 word ), arithmetic expansion, aliases, brace expansion, tilde
171 expansion, &> and >& redirection of stdout+stderr, etc.
178 Enable help builtin in hush. Code size + ~1 kbyte.
180 config HUSH_INTERACTIVE
181 bool "Interactive mode"
185 Enable interactive mode (prompt and command editing).
186 Without this, hush simply reads and executes commands
187 from stdin just like a shell script from the file.
188 No prompt, no PS1/PS2 magic shell variables.
193 depends on HUSH_INTERACTIVE
195 Enable job control: Ctrl-Z backgrounds, Ctrl-C interrupts current
196 command (not entire shell), fg/bg builtins work. Without this option,
197 "cmd &" still works by simply spawning a process and immediately
198 prompting for next command (or executing next command in a script),
199 but no separate process group is formed.
202 bool "Process substitution"
206 Enable process substitution `command` and $(command) in hush.
209 bool "Support if/then/elif/else/fi"
213 Enable if/then/elif/else/fi in hush.
216 bool "Support for, while and until loops"
220 Enable for, while and until loops in hush.
221 As of 2008-07, break and continue statements are not supported.
224 bool "Support case ... esac statement"
228 Enable case ... esac statement in hush. +400 bytes.
231 bool "lash (deprecated: aliased to hush)"
235 lash is deprecated and will be removed, please migrate to hush.
238 bool "msh (deprecated: please use hush)"
241 The minix shell (adds just 30k) is quite complete and handles things
242 like for/do/done, case/esac and all the things you expect a Bourne
243 shell to do. It is not always pedantically correct about Bourne
244 shell grammar (try running the shell testscript "tests/sh.testcases"
245 on it and compare vs bash) but for most things it works quite well.
246 It uses only vfork, so it can be used on uClinux systems.
248 msh is deprecated and will be removed, please migrate to hush.
249 If there is a feature msh has but hush does not, please let us know.
251 comment "Bourne Shell Options"
252 depends on MSH || LASH || HUSH || ASH
254 config SH_MATH_SUPPORT
255 bool "POSIX math support"
257 depends on ASH || HUSH
259 Enable math support in the shell via $((...)) syntax.
261 config SH_MATH_SUPPORT_64
262 bool "Extend POSIX math support to 64 bit"
264 depends on SH_MATH_SUPPORT
266 Enable 64-bit math support in the shell. This will make the shell
267 slightly larger, but will allow computation with very large numbers.
268 This is not in POSIX, so do not rely on this in portable code.
270 config FEATURE_SH_EXTRA_QUIET
271 bool "Hide message on interactive shell startup"
273 depends on MSH || LASH || HUSH || ASH
275 Remove the busybox introduction when starting a shell.
277 config FEATURE_SH_STANDALONE
278 bool "Standalone shell"
280 depends on (MSH || LASH || HUSH || ASH) && FEATURE_PREFER_APPLETS
282 This option causes busybox shells to use busybox applets
283 in preference to executables in the PATH whenever possible. For
284 example, entering the command 'ifconfig' into the shell would cause
285 busybox to use the ifconfig busybox applet. Specifying the fully
286 qualified executable name, such as '/sbin/ifconfig' will still
287 execute the /sbin/ifconfig executable on the filesystem. This option
288 is generally used when creating a statically linked version of busybox
289 for use as a rescue shell, in the event that you screw up your system.
291 This is implemented by re-execing /proc/self/exe (typically)
292 with right parameters. Some selected applets ("NOFORK" applets)
293 can even be executed without creating new process.
294 Instead, busybox will call <applet>_main() internally.
296 However, this causes problems in chroot jails without mounted /proc
297 and with ps/top (command name can be shown as 'exe' for applets
300 # Note that this will *also* cause applets to take precedence
301 # over shell builtins of the same name. So turning this on will
302 # eliminate any performance gained by turning on the builtin "echo"
303 # and "test" commands in ash.
305 # Note that when using this option, the shell will attempt to directly
306 # run '/bin/busybox'. If you do not have the busybox binary sitting in
307 # that exact location with that exact name, this option will not work at
310 config FEATURE_SH_NOFORK
311 bool "Run 'nofork' applets directly"
313 depends on (MSH || LASH || HUSH || ASH) && FEATURE_PREFER_APPLETS
315 This option causes busybox shells [currently only ash]
316 to not execute typical fork/exec/wait sequence, but call <applet>_main
317 directly, if possible. (Sometimes it is not possible: for example,
318 this is not possible in pipes).
320 This will be done only for some applets (those which are marked
321 NOFORK in include/applets.h).
323 This may significantly speed up some shell scripts.
325 This feature is relatively new. Use with care.
331 One common problem reported on the mailing list is "can't access tty;
332 job control turned off" error message which typically appears when
333 one tries to use shell with stdin/stdout opened to /dev/console.
334 This device is special - it cannot be a controlling tty.
336 Proper solution is to use correct device instead of /dev/console.
338 cttyhack provides "quick and dirty" solution to this problem.
339 It analyzes stdin with various ioctls, trying to determine whether
340 it is a /dev/ttyN or /dev/ttySN (virtual terminal or serial line).
341 If it detects one, it closes stdin/out/err and reopens that device.
342 Then it executes given program. Usage example for /etc/inittab
345 ::respawn:/bin/cttyhack /bin/sh