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