mirror of
https://github.com/sheumann/hush.git
synced 2024-08-20 04:28:57 +00:00
function old new delta skip_dash_dash - 33 +33 builtin_exit 43 48 +5 builtin_umask 121 125 +4 builtin_shift 115 119 +4 builtin_cd 71 75 +4 builtin_wait 271 274 +3 builtin_source 171 174 +3 builtin_exec 57 60 +3 builtin_eval 46 45 -1 ------------------------------------------------------------------------------ (add/remove: 1/0 grow/shrink: 7/1 up/down: 59/-1) Total: 58 bytes Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> |
||
---|---|---|
.. | ||
ash_test | ||
hush_test | ||
msh_test | ||
ash_doc.txt | ||
ash_ptr_hack.c | ||
ash.c | ||
bbsh.c | ||
brace.txt | ||
builtin_read.c | ||
builtin_read.h | ||
builtin_ulimit.c | ||
builtin_ulimit.h | ||
Config.in | ||
cttyhack.c | ||
hush_doc.txt | ||
hush_leaktool.sh | ||
hush.c | ||
Kbuild | ||
lash_unused.c | ||
match.c | ||
match.h | ||
math.c | ||
math.h | ||
msh_unused.c | ||
random.c | ||
random.h | ||
README | ||
README.job | ||
shell_common.c | ||
shell_common.h |
http://www.opengroup.org/onlinepubs/9699919799/ Open Group Base Specifications Issue 7 http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap01.html Shell & Utilities It says that any of the standard utilities may be implemented as a regular shell built-in. It gives a list of utilities which are usually implemented that way (and some of them can only be implemented as built-ins, like "alias"): alias bg cd command false fc fg getopts jobs kill newgrp pwd read true umask unalias wait http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html Shell Command Language It says that shell must implement special built-ins. Special built-ins differ from regular ones by the fact that variable assignments done on special builtin is *PRESERVED*. That is, VAR=VAL special_builtin; echo $VAR should print VAL. (Another distinction is that an error in special built-in should abort the shell, but this is not such a critical difference, and moreover, at least bash's "set" does not follow this rule, which is even codified in autoconf now...). List of special builtins: . file : [argument...] break [n] continue [n] eval [argument...] exec [command [argument...]] exit [n] export name[=word]... export -p readonly name[=word]... readonly -p return [n] set [-abCefhmnuvx] [-o option] [argument...] set [+abCefhmnuvx] [+o option] [argument...] set -- [argument...] set -o set +o shift [n] times trap n [condition...] trap [action condition...] unset [-fv] name... In practice, no one uses this obscure feature - none of these builtins gives any special reasons to play such dirty tricks. However. This section says that *function invocation* should act similar to special built-in. That is, variable assignments done on function invocation should be preserved after function invocation. This is significant: it is not unthinkable to want to run a function with some variables set to special values. But because of the above, it does not work: variable will "leak" out of the function.