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-conpatible 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.
87 config ASH_MATH_SUPPORT
88 bool "Posix math support"
92 Enable math support in the ash shell.
94 config ASH_MATH_SUPPORT_64
95 bool "Extend Posix math support to 64 bit"
97 depends on ASH_MATH_SUPPORT
99 Enable 64-bit math support in the ash shell. This will make
100 the shell slightly larger, but will allow computation with very
104 bool "Builtin getopt to parse positional parameters"
108 Enable getopts builtin in the ash shell.
110 config ASH_BUILTIN_ECHO
111 bool "Builtin version of 'echo'"
115 Enable support for echo, builtin to ash.
117 config ASH_BUILTIN_PRINTF
118 bool "Builtin version of 'printf'"
122 Enable support for printf, builtin to ash.
124 config ASH_BUILTIN_TEST
125 bool "Builtin version of 'test'"
129 Enable support for test, builtin to ash.
132 bool "'command' command to override shell builtins"
136 Enable support for the ash 'command' builtin, which allows
137 you to run the specified command with the specified arguments,
138 even when there is an ash builtin command with the same name.
141 bool "Check for new mail on interactive shells"
145 Enable "check for new mail" in the ash shell.
147 config ASH_OPTIMIZE_FOR_SIZE
148 bool "Optimize for size instead of speed"
152 Compile ash for reduced size at the price of speed.
154 config ASH_RANDOM_SUPPORT
155 bool "Pseudorandom generator and variable $RANDOM"
159 Enable pseudorandom generator and dynamic variable "$RANDOM".
160 Each read of "$RANDOM" will generate a new pseudorandom value.
161 You can reset the generator by using a specified start value.
162 After "unset RANDOM" then generator will switch off and this
163 variable will no longer have special treatment.
165 config ASH_EXPAND_PRMT
166 bool "Expand prompt string"
170 "PS#" may be contain volatile content, such as backquote commands.
171 This option recreates the prompt string from the environment
172 variable each time it is displayed.
178 hush is a very small shell (just 18k) and it has fairly complete
179 Bourne shell grammar. It even handles all the normal flow control
180 options such as if/then/elif/else/fi, for/in/do/done, while loops,
183 It does not handle case/esac, select, function, here documents ( <<
184 word ), arithmetic expansion, aliases, brace expansion, tilde
185 expansion, &> and >& redirection of stdout+stderr, etc.
192 Enable help builtin in hush. Code size + ~1 kbyte.
194 config HUSH_INTERACTIVE
195 bool "Interactive mode"
199 Enable interactive mode (prompt and command editing).
200 Without this, hush simply reads and executes commands
201 from stdin just like a shell script from the file.
202 No prompt, no PS1/PS2 magic shell variables.
207 depends on HUSH_INTERACTIVE
209 Enable job control: Ctrl-Z backgrounds, Ctrl-C interrupts current
210 command (not entire shell), fg/bg builtins work. Without this option,
211 "cmd &" still works by simply spawning a process and immediately
212 prompting for next command (or executing next command in a script),
213 but no separate process group is formed.
216 bool "Process substitution"
220 Enable process substitution `command` and $(command) in hush.
223 bool "Support if/then/elif/else/fi"
227 Enable if/then/elif/else/fi in hush.
230 bool "Support for, while and until loops"
234 Enable for, while and until loops in hush.
241 lash is deprecated and will be removed, please migrate to hush.
247 The minix shell (adds just 30k) is quite complete and handles things
248 like for/do/done, case/esac and all the things you expect a Bourne
249 shell to do. It is not always pedantically correct about Bourne
250 shell grammar (try running the shell testscript "tests/sh.testcases"
251 on it and compare vs bash) but for most things it works quite well.
252 It also uses only vfork, so it can be used on uClinux systems.
254 comment "Bourne Shell Options"
255 depends on MSH || LASH || HUSH || ASH
257 config FEATURE_SH_EXTRA_QUIET
258 bool "Hide message on interactive shell startup"
260 depends on MSH || LASH || HUSH || ASH
262 Remove the busybox introduction when starting a shell.
264 config FEATURE_SH_STANDALONE
265 bool "Standalone shell"
267 depends on (MSH || LASH || HUSH || ASH) && FEATURE_PREFER_APPLETS
269 This option causes busybox shells to use busybox applets
270 in preference to executables in the PATH whenever possible. For
271 example, entering the command 'ifconfig' into the shell would cause
272 busybox to use the ifconfig busybox applet. Specifying the fully
273 qualified executable name, such as '/sbin/ifconfig' will still
274 execute the /sbin/ifconfig executable on the filesystem. This option
275 is generally used when creating a statically linked version of busybox
276 for use as a rescue shell, in the event that you screw up your system.
278 This is implemented by re-execing /proc/self/exe (typically)
279 with right parameters. Some selected applets ("NOFORK" applets)
280 can even be executed without creating new process.
281 Instead, busybox will call <applet>_main() internally.
283 However, this causes problems in chroot jails without mounted /proc
284 and with ps/top (command name can be shown as 'exe' for applets
287 # Note that this will *also* cause applets to take precedence
288 # over shell builtins of the same name. So turning this on will
289 # eliminate any performance gained by turning on the builtin "echo"
290 # and "test" commands in ash.
292 # Note that when using this option, the shell will attempt to directly
293 # run '/bin/busybox'. If you do not have the busybox binary sitting in
294 # that exact location with that exact name, this option will not work at
297 config FEATURE_SH_NOFORK
298 bool "Run 'nofork' applets directly"
300 depends on (MSH || LASH || HUSH || ASH) && FEATURE_PREFER_APPLETS
302 This option causes busybox shells [currently only ash]
303 to not execute typical fork/exec/wait sequence, but call <applet>_main
304 directly, if possible. (Sometimes it is not possible: for example,
305 this is not possible in pipes).
307 This will be done only for some applets (those which are marked
308 NOFORK in include/applets.h).
310 This may significantly speed up some shell scripts.
312 This feature is relatively new. Use with care.
318 One common problem reported on the mailing list is "can't access tty;
319 job control turned off" error message which typically appears when
320 one tries to use shell with stdin/stdout opened to /dev/console.
321 This device is special - it cannot be a controlling tty.
323 Proper solution is to use correct device instead of /dev/console.
325 cttyhack provides "quick and dirty" solution to this problem.
326 It analyzes stdin with various ioctls, trying to determine whether
327 it is a /dev/ttyN or /dev/ttySN (virtual terminal or serial line).
328 If it detects one, it closes stdin/out/err and reopens that device.
329 Then it executes given program. Usage example for /etc/inittab
332 ::respawn:/bin/cttyhack /bin/sh