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#
# For a description of the syntax of this configuration file,
# see scripts/kbuild/config-language.txt.
#
menu "Shells"
choice
prompt "Choose your default shell"
default FEATURE_SH_IS_NONE
help
Choose a shell. The ash shell is the most bash compatible
and full featured one.
config FEATURE_SH_IS_ASH
select ASH
bool "ash"
config FEATURE_SH_IS_HUSH
select HUSH
bool "hush"
config FEATURE_SH_IS_LASH
select LASH
bool "lash"
config FEATURE_SH_IS_MSH
select MSH
bool "msh"
config FEATURE_SH_IS_NONE
bool "none"
endchoice
config ASH
bool "ash"
default n
select TEST
help
Tha 'ash' shell adds about 60k in the default configuration and is
the most complete and most pedantically correct shell included with
busybox. This shell is actually a derivative of the Debian 'dash'
shell (by Herbert Xu), which was created by porting the 'ash' shell
(written by Kenneth Almquist) from NetBSD.
comment "Ash Shell Options"
depends on ASH
config ASH_JOB_CONTROL
bool "Job control"
default y
depends on ASH
help
Enable job control in the ash shell.
config ASH_READ_NCHARS
bool "'read -n N' and 'read -s' support"
default n
depends on ASH
help
'read -n N' will return a value after N characters have been read.
'read -s' will read without echoing the user's input.
config ASH_READ_TIMEOUT
bool "'read -t S' support."
default n
depends on ASH
help
'read -t S' will return a value after S seconds have passed.
This implementation will allow fractional seconds, expressed
as a decimal fraction, e.g. 'read -t 2.5 foo'.
config ASH_ALIAS
bool "alias support"
default y
depends on ASH
help
Enable alias support in the ash shell.
config ASH_MATH_SUPPORT
bool "Posix math support"
default y
depends on ASH
help
Enable math support in the ash shell.
config ASH_MATH_SUPPORT_64
bool "Extend Posix math support to 64 bit"
default n
depends on ASH_MATH_SUPPORT
help
Enable 64-bit math support in the ash shell. This will make
the shell slightly larger, but will allow computation with very
large numbers.
config ASH_GETOPTS
bool "Builtin getopt to parse positional parameters"
default n
depends on ASH
help
Enable getopts builtin in the ash shell.
config ASH_BUILTIN_ECHO
bool "Builtin version of 'echo'"
default y
select ECHO
depends on ASH
help
Enable support for echo, builtin to ash.
config ASH_BUILTIN_TEST
bool "Builtin version of 'test'"
default y
select TEST
depends on ASH
help
Enable support for test, builtin to ash.
config ASH_CMDCMD
bool "'command' command to override shell builtins"
default n
depends on ASH
help
Enable support for the ash 'command' builtin, which allows
you to run the specified command with the specified arguments,
even when there is an ash builtin command with the same name.
config ASH_MAIL
bool "Check for new mail on interactive shells"
default y
depends on ASH
help
Enable "check for new mail" in the ash shell.
config ASH_OPTIMIZE_FOR_SIZE
bool "Optimize for size instead of speed"
default y
depends on ASH
help
Compile ash for reduced size at the price of speed.
config ASH_RANDOM_SUPPORT
bool "Pseudorandom generator and variable $RANDOM"
default n
depends on ASH
help
Enable pseudorandom generator and dynamic variable "$RANDOM".
Each read of "$RANDOM" will generate a new pseudorandom value.
You can reset the generator by using a specified start value.
After "unset RANDOM" then generator will switch off and this
variable will no longer have special treatment.
config ASH_EXPAND_PRMT
bool "Expand prompt string"
default n
depends on ASH
help
"PS#" may be contain volatile content, such as backquote commands.
This option recreates the prompt string from the environment
variable each time it is displayed.
config HUSH
bool "hush"
default n
select TRUE
select FALSE
select TEST
help
hush is a very small shell (just 18k) and it has fairly complete
Bourne shell grammar. It even handles all the normal flow control
options such as if/then/elif/else/fi, for/in/do/done, while loops,
etc.
It does not handle case/esac, select, function, here documents ( <<
word ), arithmetic expansion, aliases, brace expansion, tilde
expansion, &> and >& redirection of stdout+stderr, etc.
config HUSH_INTERACTIVE
bool "Interactive mode"
default y
depends on HUSH
help
Enable interactive mode (prompt and command editing).
Without this, hush simply reads and executes commands
from stdin just like a shell script from the file.
No prompt, no PS1/PS2 magic shell variables.
config HUSH_JOB
bool "Job control"
default n
depends on HUSH_INTERACTIVE
help
Enable job control: Ctrl-Z backgrounds, Ctrl-C interrupts current
command (not entire shell), fg/bg builtins work. Without this option,
"cmd &" still works by simply spawning a process and immediately
prompting for next command (or executing next command in a script),
but no separate process group is formed.
config LASH
bool "lash"
default n
select TRUE
select FALSE
select TEST
help
lash is the very smallest shell (adds just 10k) and it is quite
usable as a command prompt, but it is not suitable for any but the
most trivial scripting (such as an initrd that calls insmod a few
times) since it does not understand any Bourne shell grammar. It
does handle pipes, redirects, and job control though. Adding in
command editing makes it a very nice lightweight command prompt.
config MSH
bool "msh"
default n
select TRUE
select FALSE
select TEST
help
The minix shell (adds just 30k) is quite complete and handles things
like for/do/done, case/esac and all the things you expect a Bourne
shell to do. It is not always pedantically correct about Bourne
shell grammar (try running the shell testscript "tests/sh.testcases"
on it and compare vs bash) but for most things it works quite well.
It also uses only vfork, so it can be used on uClinux systems.
comment "Bourne Shell Options"
depends on MSH || LASH || HUSH || ASH
config FEATURE_SH_EXTRA_QUIET
bool "Hide message on interactive shell startup"
default n
depends on MSH || LASH || HUSH || ASH
help
Remove the busybox introduction when starting a shell.
config FEATURE_SH_STANDALONE
bool "Standalone shell"
default n
depends on (MSH || LASH || HUSH || ASH) && FEATURE_PREFER_APPLETS
help
This option causes busybox shells to use busybox applets
in preference to executables in the PATH whenever possible. For
example, entering the command 'ifconfig' into the shell would cause
busybox to use the ifconfig busybox applet. Specifying the fully
qualified executable name, such as '/sbin/ifconfig' will still
execute the /sbin/ifconfig executable on the filesystem. This option
is generally used when creating a statically linked version of busybox
for use as a rescue shell, in the event that you screw up your system.
This is implemented by re-execing /proc/self/exe (typically)
with right parameters. Some selected applets ("NOFORK" applets)
can even be executed without creating new process.
Instead, busybox will call <applet>_main() internally.
However, this causes problems in chroot jails without mounted /proc
and with ps/top (command name can be shown as 'exe' for applets
started this way).
# untrue?
# Note that this will *also* cause applets to take precedence
# over shell builtins of the same name. So turning this on will
# eliminate any performance gained by turning on the builtin "echo"
# and "test" commands in ash.
# untrue?
# Note that when using this option, the shell will attempt to directly
# run '/bin/busybox'. If you do not have the busybox binary sitting in
# that exact location with that exact name, this option will not work at
# all.
endmenu
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