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function old new delta BB_EXECVP_or_die - 47 +47 time_main 1042 1043 +1 chrt_main 371 364 -7 ionice_main 292 282 -10 setsid_main 69 56 -13 nohup_main 236 223 -13 cttyhack_main 266 253 -13 chroot_main 94 81 -13 chpst_main 746 733 -13 timeout_main 297 279 -18 taskset_main 541 522 -19 vfork_child 67 45 -22 parse 975 953 -22 lpd_main 770 748 -22 launch_helper 192 170 -22 tcpudpsvd_main 1810 1782 -28 nice_main 190 156 -34 env_main 242 206 -36 run_command 221 174 -47 ------------------------------------------------------------------------------ (add/remove: 1/0 grow/shrink: 1/17 up/down: 48/-352) Total: -304 bytes Signed-off-by: Pascal Bellard <pascal.bellard@ads-lu.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> |
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| .. | ||
| ash_test | ||
| hush_test | ||
| msh_test | ||
| ash_doc.txt | ||
| ash_ptr_hack.c | ||
| ash.c | ||
| bbsh.c | ||
| brace.txt | ||
| Config.src | ||
| cttyhack.c | ||
| hush_doc.txt | ||
| hush_leaktool.sh | ||
| hush.c | ||
| Kbuild.src | ||
| match.c | ||
| match.h | ||
| math.c | ||
| math.h | ||
| 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 are *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 configure logic 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 also 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.