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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-05 18:33:23 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-05 18:33:23 +0000 |
commit | 1d5cace9db9aef76f26b2d7ba54bbb76443b00b2 (patch) | |
tree | 314a15dd1aa103da13bdc83ba1d2105a290bc5ba /examples/functions/external | |
parent | Initial commit. (diff) | |
download | bash-upstream.tar.xz bash-upstream.zip |
Adding upstream version 5.0.upstream/5.0upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'examples/functions/external')
-rw-r--r-- | examples/functions/external | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/examples/functions/external b/examples/functions/external new file mode 100644 index 0000000..c2e52cd --- /dev/null +++ b/examples/functions/external @@ -0,0 +1,50 @@ +# Contributed by Noah Friedman. + +# To avoid using a function in bash, you can use the `builtin' or +# `command' builtins, but neither guarantees that you use an external +# program instead of a bash builtin if there's a builtin by that name. So +# this function can be used like `command' except that it guarantees the +# program is external by first disabling any builtin by that name. After +# the command is done executing, the state of the builtin is restored. +function external () +{ + local state="" + local exit_status + + if builtin_p "$1"; then + state="builtin" + enable -n "$1" + fi + + command "$@" + exit_status=$? + + if [ "$state" = "builtin" ]; then + enable "$1" + fi + + return ${exit_status} +} + +# What is does is tell you if a particular keyword is currently enabled as +# a shell builtin. It does NOT tell you if invoking that keyword will +# necessarily run the builtin. For that, do something like +# +# test "$(builtin type -type [keyword])" = "builtin" +# +# Note also, that disabling a builtin with "enable -n" will make builtin_p +# return false, since the builtin is no longer available. +function builtin_p () +{ + local word + + set $(builtin type -all -type "$1") + + for word in "$@" ; do + if [ "${word}" = "builtin" ]; then + return 0 + fi + done + + return 1 +} |