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 $RANDOM variable"
143 Enable pseudorandom generator and dynamic variable "$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" the 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 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 will compile and work on no-mmu systems.
169 It does not handle select, functions, here documents ( <<
170 word ), aliases, brace expansion, tilde expansion,
171 &> 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.
223 bool "Support case ... esac statement"
227 Enable case ... esac statement in hush. +400 bytes.
230 bool "lash (deprecated: aliased to hush)"
234 lash is deprecated and will be removed, please migrate to hush.
237 bool "msh (deprecated: please use 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 uses only vfork, so it can be used on uClinux systems.
247 msh is deprecated and will be removed, please migrate to hush.
248 If there is a feature msh has but hush does not, please let us know.
250 comment "Bourne Shell Options"
251 depends on MSH || LASH || HUSH || ASH
253 config SH_MATH_SUPPORT
254 bool "POSIX math support"
256 depends on ASH || HUSH
258 Enable math support in the shell via $((...)) syntax.
260 config SH_MATH_SUPPORT_64
261 bool "Extend POSIX math support to 64 bit"
263 depends on SH_MATH_SUPPORT
265 Enable 64-bit math support in the shell. This will make the shell
266 slightly larger, but will allow computation with very large numbers.
267 This is not in POSIX, so do not rely on this in portable code.
269 config FEATURE_SH_EXTRA_QUIET
270 bool "Hide message on interactive shell startup"
272 depends on MSH || LASH || HUSH || ASH
274 Remove the busybox introduction when starting a shell.
276 config FEATURE_SH_STANDALONE
277 bool "Standalone shell"
279 depends on (MSH || LASH || HUSH || ASH) && FEATURE_PREFER_APPLETS
281 This option causes busybox shells to use busybox applets
282 in preference to executables in the PATH whenever possible. For
283 example, entering the command 'ifconfig' into the shell would cause
284 busybox to use the ifconfig busybox applet. Specifying the fully
285 qualified executable name, such as '/sbin/ifconfig' will still
286 execute the /sbin/ifconfig executable on the filesystem. This option
287 is generally used when creating a statically linked version of busybox
288 for use as a rescue shell, in the event that you screw up your system.
290 This is implemented by re-execing /proc/self/exe (typically)
291 with right parameters. Some selected applets ("NOFORK" applets)
292 can even be executed without creating new process.
293 Instead, busybox will call <applet>_main() internally.
295 However, this causes problems in chroot jails without mounted /proc
296 and with ps/top (command name can be shown as 'exe' for applets
299 # Note that this will *also* cause applets to take precedence
300 # over shell builtins of the same name. So turning this on will
301 # eliminate any performance gained by turning on the builtin "echo"
302 # and "test" commands in ash.
304 # Note that when using this option, the shell will attempt to directly
305 # run '/bin/busybox'. If you do not have the busybox binary sitting in
306 # that exact location with that exact name, this option will not work at
309 config FEATURE_SH_NOFORK
310 bool "Run 'nofork' applets directly"
312 depends on (MSH || LASH || HUSH || ASH) && FEATURE_PREFER_APPLETS
314 This option causes busybox shells [currently only ash]
315 to not execute typical fork/exec/wait sequence, but call <applet>_main
316 directly, if possible. (Sometimes it is not possible: for example,
317 this is not possible in pipes).
319 This will be done only for some applets (those which are marked
320 NOFORK in include/applets.h).
322 This may significantly speed up some shell scripts.
324 This feature is relatively new. Use with care.
330 One common problem reported on the mailing list is "can't access tty;
331 job control turned off" error message which typically appears when
332 one tries to use shell with stdin/stdout opened to /dev/console.
333 This device is special - it cannot be a controlling tty.
335 Proper solution is to use correct device instead of /dev/console.
337 cttyhack provides "quick and dirty" solution to this problem.
338 It analyzes stdin with various ioctls, trying to determine whether
339 it is a /dev/ttyN or /dev/ttySN (virtual terminal or serial line).
340 If it detects one, it closes stdin/out/err and reopens that device.
341 Then it executes given program. Usage example for /etc/inittab
344 ::respawn:/bin/cttyhack /bin/sh