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 config ASH_BASH_COMPAT
47 bool "bash-compatible extensions"
51 Enable bash-compatible extensions.
53 config ASH_JOB_CONTROL
58 Enable job control in the ash shell.
60 config ASH_READ_NCHARS
61 bool "'read -n N' and 'read -s' support"
65 'read -n N' will return a value after N characters have been read.
66 'read -s' will read without echoing the user's input.
68 config ASH_READ_TIMEOUT
69 bool "'read -t S' support"
73 'read -t S' will return a value after S seconds have passed.
74 This implementation will allow fractional seconds, expressed
75 as a decimal fraction, e.g. 'read -t 2.5 foo'.
82 Enable alias support in the ash shell.
85 bool "Builtin getopt to parse positional parameters"
89 Enable getopts builtin in the ash shell.
91 config ASH_BUILTIN_ECHO
92 bool "Builtin version of 'echo'"
96 Enable support for echo, builtin to ash.
98 config ASH_BUILTIN_PRINTF
99 bool "Builtin version of 'printf'"
103 Enable support for printf, builtin to ash.
105 config ASH_BUILTIN_TEST
106 bool "Builtin version of 'test'"
110 Enable support for test, builtin to ash.
113 bool "'command' command to override shell builtins"
117 Enable support for the ash 'command' builtin, which allows
118 you to run the specified command with the specified arguments,
119 even when there is an ash builtin command with the same name.
122 bool "Check for new mail on interactive shells"
126 Enable "check for new mail" in the ash shell.
128 config ASH_OPTIMIZE_FOR_SIZE
129 bool "Optimize for size instead of speed"
133 Compile ash for reduced size at the price of speed.
135 config ASH_RANDOM_SUPPORT
136 bool "Pseudorandom generator and $RANDOM variable"
140 Enable pseudorandom generator and dynamic variable "$RANDOM".
141 Each read of "$RANDOM" will generate a new pseudorandom value.
142 You can reset the generator by using a specified start value.
143 After "unset RANDOM" the generator will switch off and this
144 variable will no longer have special treatment.
146 config ASH_EXPAND_PRMT
147 bool "Expand prompt string"
151 "PS#" may contain volatile content, such as backquote commands.
152 This option recreates the prompt string from the environment
153 variable each time it is displayed.
159 hush is a small shell (22k). It handles the normal flow control
160 constructs such as if/then/elif/else/fi, for/in/do/done, while loops,
161 case/esac. Redirections, here documents, $((arithmetic))
162 and functions are supported.
164 It will compile and work on no-mmu systems.
166 It does not handle select, aliases, brace expansion,
167 tilde expansion, &>file and >&file redirection of stdout+stderr.
169 config HUSH_BASH_COMPAT
170 bool "bash-compatible extensions"
174 Enable bash-compatible extensions.
181 Enable help builtin in hush. Code size + ~1 kbyte.
183 config HUSH_INTERACTIVE
184 bool "Interactive mode"
188 Enable interactive mode (prompt and command editing).
189 Without this, hush simply reads and executes commands
190 from stdin just like a shell script from the file.
191 No prompt, no PS1/PS2 magic shell variables.
196 depends on HUSH_INTERACTIVE
198 Enable job control: Ctrl-Z backgrounds, Ctrl-C interrupts current
199 command (not entire shell), fg/bg builtins work. Without this option,
200 "cmd &" still works by simply spawning a process and immediately
201 prompting for next command (or executing next command in a script),
202 but no separate process group is formed.
205 bool "Process substitution"
209 Enable process substitution `command` and $(command) in hush.
212 bool "Support if/then/elif/else/fi"
216 Enable if/then/elif/else/fi in hush.
219 bool "Support for, while and until loops"
223 Enable for, while and until loops in hush.
226 bool "Support case ... esac statement"
230 Enable case ... esac statement in hush. +400 bytes.
232 config HUSH_FUNCTIONS
233 bool "Support funcname() { commands; } syntax"
237 Enable support for shell functions in hush. +800 bytes.
240 bool "Support local builtin"
242 depends on HUSH_FUNCTIONS
244 Enable support for local variables in functions.
247 bool "Support export '-n' option"
251 Enable support for export '-n' option in hush. It is a bash extension.
254 bool "lash (deprecated: aliased to hush)"
258 lash is deprecated and will be removed, please migrate to hush.
261 bool "msh (deprecated: please use hush)"
265 msh is deprecated and will be removed, please migrate to hush.
266 If there is a feature msh has but hush does not, please let us know.
268 # The minix shell (adds just 30k) is quite complete and handles things
269 # like for/do/done, case/esac and all the things you expect a Bourne
270 # shell to do. It is not always pedantically correct about Bourne
271 # shell grammar (try running the shell testscript "tests/sh.testcases"
272 # on it and compare vs bash) but for most things it works quite well.
273 # It uses only vfork, so it can be used on uClinux systems.
276 config SH_MATH_SUPPORT
277 bool "POSIX math support"
279 depends on ASH || HUSH
281 Enable math support in the shell via $((...)) syntax.
283 config SH_MATH_SUPPORT_64
284 bool "Extend POSIX math support to 64 bit"
286 depends on SH_MATH_SUPPORT
288 Enable 64-bit math support in the shell. This will make the shell
289 slightly larger, but will allow computation with very large numbers.
290 This is not in POSIX, so do not rely on this in portable code.
292 config FEATURE_SH_EXTRA_QUIET
293 bool "Hide message on interactive shell startup"
295 depends on MSH || LASH || HUSH || ASH
297 Remove the busybox introduction when starting a shell.
299 config FEATURE_SH_STANDALONE
300 bool "Standalone shell"
302 depends on (MSH || LASH || HUSH || ASH) && FEATURE_PREFER_APPLETS
304 This option causes busybox shells to use busybox applets
305 in preference to executables in the PATH whenever possible. For
306 example, entering the command 'ifconfig' into the shell would cause
307 busybox to use the ifconfig busybox applet. Specifying the fully
308 qualified executable name, such as '/sbin/ifconfig' will still
309 execute the /sbin/ifconfig executable on the filesystem. This option
310 is generally used when creating a statically linked version of busybox
311 for use as a rescue shell, in the event that you screw up your system.
313 This is implemented by re-execing /proc/self/exe (typically)
314 with right parameters. Some selected applets ("NOFORK" applets)
315 can even be executed without creating new process.
316 Instead, busybox will call <applet>_main() internally.
318 However, this causes problems in chroot jails without mounted /proc
319 and with ps/top (command name can be shown as 'exe' for applets
322 # Note that this will *also* cause applets to take precedence
323 # over shell builtins of the same name. So turning this on will
324 # eliminate any performance gained by turning on the builtin "echo"
325 # and "test" commands in ash.
327 # Note that when using this option, the shell will attempt to directly
328 # run '/bin/busybox'. If you do not have the busybox binary sitting in
329 # that exact location with that exact name, this option will not work at
332 config FEATURE_SH_NOFORK
333 bool "Run 'nofork' applets directly"
335 depends on (MSH || LASH || HUSH || ASH) && FEATURE_PREFER_APPLETS
337 This option causes busybox shells [currently only ash]
338 to not execute typical fork/exec/wait sequence, but call <applet>_main
339 directly, if possible. (Sometimes it is not possible: for example,
340 this is not possible in pipes).
342 This will be done only for some applets (those which are marked
343 NOFORK in include/applets.h).
345 This may significantly speed up some shell scripts.
347 This feature is relatively new. Use with care.
353 One common problem reported on the mailing list is "can't access tty;
354 job control turned off" error message which typically appears when
355 one tries to use shell with stdin/stdout opened to /dev/console.
356 This device is special - it cannot be a controlling tty.
358 Proper solution is to use correct device instead of /dev/console.
360 cttyhack provides "quick and dirty" solution to this problem.
361 It analyzes stdin with various ioctls, trying to determine whether
362 it is a /dev/ttyN or /dev/ttySN (virtual terminal or serial line).
363 If it detects one, it closes stdin/out/err and reopens that device.
364 Then it executes given program. Usage example for /etc/inittab
367 ::respawn:/bin/cttyhack /bin/sh