chat: new applet by dronnikov AT gmail.com. With all options on:

function                                             old     new   delta
chat_main                                              -    1230   +1230
unescape                                               -     135    +135
packed_usage                                       23802   23922    +120
signal_handler                                       123     131      +8
input_backward                                       123     128      +5
applet_names                                        1775    1780      +5
applet_main                                         1076    1080      +4
applet_nameofs                                       538     540      +2
exitcode                                               -       1      +1
------------------------------------------------------------------------------
(add/remove: 3/0 grow/shrink: 6/0 up/down: 1510/0)           Total: 1510 bytes

include/applets.h

@@ -93,6 +93,7 @@ USE_BZIP2(APPLET(bzip2, _BB_DIR_USR_BIN, _BB_SUID_NEVER))
 USE_CAL(APPLET(cal, _BB_DIR_USR_BIN, _BB_SUID_NEVER))
 USE_CAT(APPLET_NOFORK(cat, cat, _BB_DIR_BIN, _BB_SUID_NEVER, cat))
 USE_CATV(APPLET(catv, _BB_DIR_BIN, _BB_SUID_NEVER))
+USE_CHAT(APPLET(chat, _BB_DIR_USR_BIN, _BB_SUID_NEVER))
 USE_CHATTR(APPLET(chattr, _BB_DIR_BIN, _BB_SUID_NEVER))
 USE_CHCON(APPLET(chcon, _BB_DIR_USR_BIN, _BB_SUID_NEVER))
 USE_CHGRP(APPLET_NOEXEC(chgrp, chgrp, _BB_DIR_BIN, _BB_SUID_NEVER, chgrp))

include/usage.h

@@ -204,6 +204,15 @@ USE_FEATURE_BRCTL_FANCY("\n" \
        "	-e	End each line with $\n" \
        "	-t	Show tabs as ^I\n" \
        "	-v	Don't use ^x or M-x escapes"
+
+#define chat_trivial_usage \
+       "EXPECT [SEND [EXPECT [SEND...]]]"
+#define chat_full_usage \
+       "Useful for interacting with a modem connected to stdin/stdout.\n" \
+       "A script consists of one or more \"expect-send\" pairs of strings,\n" \
+       "each pair is a pair of arguments. Example:\n" \
+       "chat '' ATZ OK ATD123456 CONNECT '' ogin: pppuser word: ppppass '~'" \
+
 #define chattr_trivial_usage \
        "[-R] [-+=AacDdijsStTu] [-v version] files..."
 #define chattr_full_usage \

miscutils/Config.in

@@ -19,6 +19,66 @@ config BBCONFIG
 	  The bbconfig applet will print the config file with which
 	  busybox was built.
 
+config CHAT
+	bool "chat"
+	default n
+	help
+	  Simple chat utility.
+
+config FEATURE_CHAT_NOFAIL
+	bool "Enable NOFAIL expect strings"
+	default y
+	help
+	  When enabled expect strings which are started with a dash trigger
+	  no-fail mode. That is when expectation is not met within timeout
+	  the script is not terminated but sends next SEND string and waits
+	  for next EXPECT string. This allows to compose far more flexible
+	  scripts.
+
+config FEATURE_CHAT_TTY_HIFI
+	bool "Force STDIN to be a TTY"
+	default n
+	help
+	  Original chat always treats STDIN as a TTY device and sets for it
+	  so-called raw mode. This option turns on such behaviour.
+
+config FEATURE_CHAT_IMPLICIT_CR
+	bool "Enable implicit Carriage Return"
+	default y
+	help
+	  When enabled make chat to terminate all SEND strings with a "\r"
+	  unless "\c" is met anywhere in the string.
+
+config FEATURE_CHAT_SWALLOW_OPTS
+	bool "Swallow options"
+	default n
+	help
+	  Busybox chat require no options. To make it not fail when used
+	  in place of original chat (which has a bunch of options) turn
+	  this on.
+
+config FEATURE_CHAT_SEND_ESCAPES
+	bool "Support weird SEND escapes"
+	default n
+	help
+	  Original chat uses some escape sequences in SEND arguments which
+	  are not sent to device but rather performs special actions.
+	  E.g. "\K" means to send a break sequence to device.
+	  "\d" delays execution for a second, "\p" -- for a 1/100 of second.
+	  Before turning this option on think twice: do you really need them?
+
+config FEATURE_CHAT_VAR_ABORT_LEN
+	bool "Support variable-length ABORT conditions"
+	default n
+	help
+	  Original chat uses fixed 50-bytes length ABORT conditions. Say N here.
+
+config FEATURE_CHAT_CLR_ABORT
+	bool "Support revoking of ABORT conditions"
+	default n
+	help
+	  Support CLR_ABORT directive.
+
 config CHRT
 	bool "chrt"
 	default n

miscutils/Kbuild

@@ -7,6 +7,7 @@
 lib-y:=
 lib-$(CONFIG_ADJTIMEX)    += adjtimex.o
 lib-$(CONFIG_BBCONFIG)    += bbconfig.o
+lib-$(CONFIG_CHAT)        += chat.o
 lib-$(CONFIG_CHRT)        += chrt.o
 lib-$(CONFIG_CROND)       += crond.o
 lib-$(CONFIG_CRONTAB)     += crontab.o