1# 2# For a description of the syntax of this configuration file, 3# see scripts/kbuild/config-language.txt. 4# 5 6menu "Shells" 7 8choice 9 prompt "Choose your default shell" 10 default FEATURE_SH_IS_NONE 11 help 12 Choose a shell. The ash shell is the most bash compatible 13 and full featured one. 14 15config FEATURE_SH_IS_ASH 16 select ASH 17 bool "ash" 18 depends on !NOMMU 19 20config FEATURE_SH_IS_HUSH 21 select HUSH 22 bool "hush" 23 24####config FEATURE_SH_IS_LASH 25#### select LASH 26#### bool "lash" 27 28####config FEATURE_SH_IS_MSH 29#### select MSH 30#### bool "msh" 31 32config FEATURE_SH_IS_NONE 33 bool "none" 34 35endchoice 36 37config ASH 38 bool "ash" 39 default n 40 depends on !NOMMU 41 help 42 Tha 'ash' shell adds about 60k in the default configuration and is 43 the most complete and most pedantically correct shell included with 44 busybox. This shell is actually a derivative of the Debian 'dash' 45 shell (by Herbert Xu), which was created by porting the 'ash' shell 46 (written by Kenneth Almquist) from NetBSD. 47 48config ASH_BASH_COMPAT 49 bool "bash-compatible extensions" 50 default y 51 depends on ASH 52 help 53 Enable bash-compatible extensions. 54 55config ASH_JOB_CONTROL 56 bool "Job control" 57 default y 58 depends on ASH 59 help 60 Enable job control in the ash shell. 61 62config ASH_ALIAS 63 bool "alias support" 64 default y 65 depends on ASH 66 help 67 Enable alias support in the ash shell. 68 69config ASH_GETOPTS 70 bool "Builtin getopt to parse positional parameters" 71 default n 72 depends on ASH 73 help 74 Enable getopts builtin in the ash shell. 75 76config ASH_BUILTIN_ECHO 77 bool "Builtin version of 'echo'" 78 default y 79 depends on ASH 80 help 81 Enable support for echo, builtin to ash. 82 83config ASH_BUILTIN_PRINTF 84 bool "Builtin version of 'printf'" 85 default y 86 depends on ASH 87 help 88 Enable support for printf, builtin to ash. 89 90config ASH_BUILTIN_TEST 91 bool "Builtin version of 'test'" 92 default y 93 depends on ASH 94 help 95 Enable support for test, builtin to ash. 96 97config ASH_CMDCMD 98 bool "'command' command to override shell builtins" 99 default n 100 depends on ASH 101 help 102 Enable support for the ash 'command' builtin, which allows 103 you to run the specified command with the specified arguments, 104 even when there is an ash builtin command with the same name. 105 106config ASH_MAIL 107 bool "Check for new mail on interactive shells" 108 default y 109 depends on ASH 110 help 111 Enable "check for new mail" in the ash shell. 112 113config ASH_OPTIMIZE_FOR_SIZE 114 bool "Optimize for size instead of speed" 115 default y 116 depends on ASH 117 help 118 Compile ash for reduced size at the price of speed. 119 120config ASH_RANDOM_SUPPORT 121 bool "Pseudorandom generator and $RANDOM variable" 122 default n 123 depends on ASH 124 help 125 Enable pseudorandom generator and dynamic variable "$RANDOM". 126 Each read of "$RANDOM" will generate a new pseudorandom value. 127 You can reset the generator by using a specified start value. 128 After "unset RANDOM" the generator will switch off and this 129 variable will no longer have special treatment. 130 131config ASH_EXPAND_PRMT 132 bool "Expand prompt string" 133 default n 134 depends on ASH 135 help 136 "PS#" may contain volatile content, such as backquote commands. 137 This option recreates the prompt string from the environment 138 variable each time it is displayed. 139 140config HUSH 141 bool "hush" 142 default n 143 help 144 hush is a small shell (22k). It handles the normal flow control 145 constructs such as if/then/elif/else/fi, for/in/do/done, while loops, 146 case/esac. Redirections, here documents, $((arithmetic)) 147 and functions are supported. 148 149 It will compile and work on no-mmu systems. 150 151 It does not handle select, aliases, brace expansion, 152 tilde expansion, &>file and >&file redirection of stdout+stderr. 153 154config HUSH_BASH_COMPAT 155 bool "bash-compatible extensions" 156 default y 157 depends on HUSH 158 help 159 Enable bash-compatible extensions. 160 161config HUSH_HELP 162 bool "help builtin" 163 default n 164 depends on HUSH 165 help 166 Enable help builtin in hush. Code size + ~1 kbyte. 167 168config HUSH_INTERACTIVE 169 bool "Interactive mode" 170 default y 171 depends on HUSH 172 help 173 Enable interactive mode (prompt and command editing). 174 Without this, hush simply reads and executes commands 175 from stdin just like a shell script from a file. 176 No prompt, no PS1/PS2 magic shell variables. 177 178config HUSH_JOB 179 bool "Job control" 180 default n 181 depends on HUSH_INTERACTIVE 182 help 183 Enable job control: Ctrl-Z backgrounds, Ctrl-C interrupts current 184 command (not entire shell), fg/bg builtins work. Without this option, 185 "cmd &" still works by simply spawning a process and immediately 186 prompting for next command (or executing next command in a script), 187 but no separate process group is formed. 188 189config HUSH_TICK 190 bool "Process substitution" 191 default n 192 depends on HUSH 193 help 194 Enable process substitution `command` and $(command) in hush. 195 196config HUSH_IF 197 bool "Support if/then/elif/else/fi" 198 default n 199 depends on HUSH 200 help 201 Enable if/then/elif/else/fi in hush. 202 203config HUSH_LOOPS 204 bool "Support for, while and until loops" 205 default n 206 depends on HUSH 207 help 208 Enable for, while and until loops in hush. 209 210config HUSH_CASE 211 bool "Support case ... esac statement" 212 default n 213 depends on HUSH 214 help 215 Enable case ... esac statement in hush. +400 bytes. 216 217config HUSH_FUNCTIONS 218 bool "Support funcname() { commands; } syntax" 219 default n 220 depends on HUSH 221 help 222 Enable support for shell functions in hush. +800 bytes. 223 224config HUSH_LOCAL 225 bool "Support local builtin" 226 default n 227 depends on HUSH_FUNCTIONS 228 help 229 Enable support for local variables in functions. 230 231config HUSH_EXPORT_N 232 bool "Support export '-n' option" 233 default n 234 depends on HUSH 235 help 236 Enable support for export '-n' option in hush. It is a bash extension. 237 238config HUSH_RANDOM_SUPPORT 239 bool "Pseudorandom generator and $RANDOM variable" 240 default n 241 depends on HUSH 242 help 243 Enable pseudorandom generator and dynamic variable "$RANDOM". 244 Each read of "$RANDOM" will generate a new pseudorandom value. 245 246config LASH 247 bool "lash (deprecated: aliased to hush)" 248 default n 249 select HUSH 250 help 251 lash is deprecated and will be removed, please migrate to hush. 252 253config MSH 254 bool "msh (deprecated: please use hush)" 255 default n 256 select HUSH 257 help 258 msh is deprecated and will be removed, please migrate to hush. 259 If there is a feature msh has but hush does not, please let us know. 260 261# The minix shell (adds just 30k) is quite complete and handles things 262# like for/do/done, case/esac and all the things you expect a Bourne 263# shell to do. It is not always pedantically correct about Bourne 264# shell grammar (try running the shell testscript "tests/sh.testcases" 265# on it and compare vs bash) but for most things it works quite well. 266# It uses only vfork, so it can be used on uClinux systems. 267 268 269config SH_MATH_SUPPORT 270 bool "POSIX math support" 271 default y 272 depends on ASH || HUSH 273 help 274 Enable math support in the shell via $((...)) syntax. 275 276config SH_MATH_SUPPORT_64 277 bool "Extend POSIX math support to 64 bit" 278 default n 279 depends on SH_MATH_SUPPORT 280 help 281 Enable 64-bit math support in the shell. This will make the shell 282 slightly larger, but will allow computation with very large numbers. 283 This is not in POSIX, so do not rely on this in portable code. 284 285config FEATURE_SH_EXTRA_QUIET 286 bool "Hide message on interactive shell startup" 287 default n 288 depends on MSH || LASH || HUSH || ASH 289 help 290 Remove the busybox introduction when starting a shell. 291 292config FEATURE_SH_STANDALONE 293 bool "Standalone shell" 294 default n 295 depends on (MSH || LASH || HUSH || ASH) && FEATURE_PREFER_APPLETS 296 help 297 This option causes busybox shells to use busybox applets 298 in preference to executables in the PATH whenever possible. For 299 example, entering the command 'ifconfig' into the shell would cause 300 busybox to use the ifconfig busybox applet. Specifying the fully 301 qualified executable name, such as '/sbin/ifconfig' will still 302 execute the /sbin/ifconfig executable on the filesystem. This option 303 is generally used when creating a statically linked version of busybox 304 for use as a rescue shell, in the event that you screw up your system. 305 306 This is implemented by re-execing /proc/self/exe (typically) 307 with right parameters. Some selected applets ("NOFORK" applets) 308 can even be executed without creating new process. 309 Instead, busybox will call <applet>_main() internally. 310 311 However, this causes problems in chroot jails without mounted /proc 312 and with ps/top (command name can be shown as 'exe' for applets 313 started this way). 314# untrue? 315# Note that this will *also* cause applets to take precedence 316# over shell builtins of the same name. So turning this on will 317# eliminate any performance gained by turning on the builtin "echo" 318# and "test" commands in ash. 319# untrue? 320# Note that when using this option, the shell will attempt to directly 321# run '/bin/busybox'. If you do not have the busybox binary sitting in 322# that exact location with that exact name, this option will not work at 323# all. 324 325config FEATURE_SH_NOFORK 326 bool "Run 'nofork' applets directly" 327 default n 328 depends on (MSH || LASH || HUSH || ASH) && FEATURE_PREFER_APPLETS 329 help 330 This option causes busybox shells [currently only ash] 331 to not execute typical fork/exec/wait sequence, but call <applet>_main 332 directly, if possible. (Sometimes it is not possible: for example, 333 this is not possible in pipes). 334 335 This will be done only for some applets (those which are marked 336 NOFORK in include/applets.h). 337 338 This may significantly speed up some shell scripts. 339 340 This feature is relatively new. Use with care. 341 342config CTTYHACK 343 bool "cttyhack" 344 default n 345 help 346 One common problem reported on the mailing list is "can't access tty; 347 job control turned off" error message which typically appears when 348 one tries to use shell with stdin/stdout opened to /dev/console. 349 This device is special - it cannot be a controlling tty. 350 351 Proper solution is to use correct device instead of /dev/console. 352 353 cttyhack provides "quick and dirty" solution to this problem. 354 It analyzes stdin with various ioctls, trying to determine whether 355 it is a /dev/ttyN or /dev/ttySN (virtual terminal or serial line). 356 If it detects one, it closes stdin/out/err and reopens that device. 357 Then it executes given program. Usage example for /etc/inittab 358 (for busybox init): 359 360 ::respawn:/bin/cttyhack /bin/sh 361 362endmenu 363