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
41 Tha 'ash' shell adds about 60k in the default configuration and is
42 the most complete and most pedantically correct shell included with
43 busybox. This shell is actually a derivative of the Debian 'dash'
44 shell (by Herbert Xu), which was created by porting the 'ash' shell
45 (written by Kenneth Almquist) from NetBSD.
47 comment "Ash Shell Options"
50 config ASH_BASH_COMPAT
51 bool "bash-compatible extensions"
55 Enable bash-conpatible extensions.
57 config ASH_JOB_CONTROL
62 Enable job control in the ash shell.
64 config ASH_READ_NCHARS
65 bool "'read -n N' and 'read -s' support"
69 'read -n N' will return a value after N characters have been read.
70 'read -s' will read without echoing the user's input.
72 config ASH_READ_TIMEOUT
73 bool "'read -t S' support."
77 'read -t S' will return a value after S seconds have passed.
78 This implementation will allow fractional seconds, expressed
79 as a decimal fraction, e.g. 'read -t 2.5 foo'.
86 Enable alias support in the ash shell.
88 config ASH_MATH_SUPPORT
89 bool "Posix math support"
93 Enable math support in the ash shell.
95 config ASH_MATH_SUPPORT_64
96 bool "Extend Posix math support to 64 bit"
98 depends on ASH_MATH_SUPPORT
100 Enable 64-bit math support in the ash shell. This will make
101 the shell slightly larger, but will allow computation with very
105 bool "Builtin getopt to parse positional parameters"
109 Enable getopts builtin in the ash shell.
111 config ASH_BUILTIN_ECHO
112 bool "Builtin version of 'echo'"
117 Enable support for echo, builtin to ash.
119 config ASH_BUILTIN_TEST
120 bool "Builtin version of 'test'"
125 Enable support for test, builtin to ash.
128 bool "'command' command to override shell builtins"
132 Enable support for the ash 'command' builtin, which allows
133 you to run the specified command with the specified arguments,
134 even when there is an ash builtin command with the same name.
137 bool "Check for new mail on interactive shells"
141 Enable "check for new mail" in the ash shell.
143 config ASH_OPTIMIZE_FOR_SIZE
144 bool "Optimize for size instead of speed"
148 Compile ash for reduced size at the price of speed.
150 config ASH_RANDOM_SUPPORT
151 bool "Pseudorandom generator and variable $RANDOM"
155 Enable pseudorandom generator and dynamic variable "$RANDOM".
156 Each read of "$RANDOM" will generate a new pseudorandom value.
157 You can reset the generator by using a specified start value.
158 After "unset RANDOM" then generator will switch off and this
159 variable will no longer have special treatment.
161 config ASH_EXPAND_PRMT
162 bool "Expand prompt string"
166 "PS#" may be contain volatile content, such as backquote commands.
167 This option recreates the prompt string from the environment
168 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.
251 The minix shell (adds just 30k) is quite complete and handles things
252 like for/do/done, case/esac and all the things you expect a Bourne
253 shell to do. It is not always pedantically correct about Bourne
254 shell grammar (try running the shell testscript "tests/sh.testcases"
255 on it and compare vs bash) but for most things it works quite well.
256 It also uses only vfork, so it can be used on uClinux systems.
258 comment "Bourne Shell Options"
259 depends on MSH || LASH || HUSH || ASH
261 config FEATURE_SH_EXTRA_QUIET
262 bool "Hide message on interactive shell startup"
264 depends on MSH || LASH || HUSH || ASH
266 Remove the busybox introduction when starting a shell.
268 config FEATURE_SH_STANDALONE
269 bool "Standalone shell"
271 depends on (MSH || LASH || HUSH || ASH) && FEATURE_PREFER_APPLETS
273 This option causes busybox shells to use busybox applets
274 in preference to executables in the PATH whenever possible. For
275 example, entering the command 'ifconfig' into the shell would cause
276 busybox to use the ifconfig busybox applet. Specifying the fully
277 qualified executable name, such as '/sbin/ifconfig' will still
278 execute the /sbin/ifconfig executable on the filesystem. This option
279 is generally used when creating a statically linked version of busybox
280 for use as a rescue shell, in the event that you screw up your system.
282 This is implemented by re-execing /proc/self/exe (typically)
283 with right parameters. Some selected applets ("NOFORK" applets)
284 can even be executed without creating new process.
285 Instead, busybox will call <applet>_main() internally.
287 However, this causes problems in chroot jails without mounted /proc
288 and with ps/top (command name can be shown as 'exe' for applets
291 # Note that this will *also* cause applets to take precedence
292 # over shell builtins of the same name. So turning this on will
293 # eliminate any performance gained by turning on the builtin "echo"
294 # and "test" commands in ash.
296 # Note that when using this option, the shell will attempt to directly
297 # run '/bin/busybox'. If you do not have the busybox binary sitting in
298 # that exact location with that exact name, this option will not work at
305 One common problem reported on the mailing list is "can't access tty;
306 job control turned off" error message which typically appears when
307 one tries to use shell with stdin/stdout opened to /dev/console.
308 This device is special - it cannot be a controlling tty.
310 Proper solution is to use correct device instead of /dev/console.
312 cttyhack provides "quick and dirty" solution to this problem.
313 It analyzes stdin with various ioctls, trying to determine whether
314 it is a /dev/ttyN or /dev/ttySN (virtual terminal or serial line).
315 If it detects one, it closes stdin/out/err and reopens that device.
316 Then it executes given program. Usage example for /etc/inittab
319 ::respawn:/bin/cttyhack /bin/sh