1# Contributed by Noah Friedman.
2
3# To avoid using a function in bash, you can use the `builtin' or
4# `command' builtins, but neither guarantees that you use an external
5# program instead of a bash builtin if there's a builtin by that name.  So
6# this function can be used like `command' except that it guarantees the
7# program is external by first disabling any builtin by that name.  After
8# the command is done executing, the state of the builtin is restored. 
9function external ()
10{
11 local state=""
12 local exit_status
13  
14    if builtin_p "$1"; then
15       state="builtin"
16       enable -n "$1"
17    fi
18
19    command "$@"
20    exit_status=$?
21
22    if [ "$state" = "builtin" ]; then
23       enable "$1"
24    fi
25
26    return ${exit_status}
27}
28
29# What is does is tell you if a particular keyword is currently enabled as
30# a shell builtin.  It does NOT tell you if invoking that keyword will
31# necessarily run the builtin.  For that, do something like
32#
33#       test "$(builtin type -type [keyword])" = "builtin"
34#
35# Note also, that disabling a builtin with "enable -n" will make builtin_p
36# return false, since the builtin is no longer available.
37function builtin_p ()
38{
39 local word
40
41    set $(builtin type -all -type "$1")
42
43    for word in "$@" ; do
44       if [ "${word}" = "builtin" ]; then
45          return 0
46       fi
47    done
48
49    return 1
50}
51