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author | Tom Ryder <tom@sanctum.geek.nz> | 2017-04-05 20:06:39 +1200 |
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committer | Tom Ryder <tom@sanctum.geek.nz> | 2017-04-05 20:46:47 +1200 |
commit | c8ab406749124d2e762ad5cf53963070113afd0f (patch) | |
tree | 54c9721a06957ebe7098a211eea803b0230c0f5d /bin/maybe.sh | |
parent | Handle POSIX correctness in ~/.bash_profile (diff) | |
download | dotfiles-c8ab406749124d2e762ad5cf53963070113afd0f.tar.gz dotfiles-c8ab406749124d2e762ad5cf53963070113afd0f.zip |
Apply runtime shebanging to POSIX shell
Diffstat (limited to 'bin/maybe.sh')
-rw-r--r-- | bin/maybe.sh | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/bin/maybe.sh b/bin/maybe.sh new file mode 100644 index 00000000..6e5c8658 --- /dev/null +++ b/bin/maybe.sh @@ -0,0 +1,23 @@ +# Exit with success or failure with a given probability +self=maybe + +# Figure out numerator and denominator from arguments +case $# in + 0) num=1 den=2 ;; + 1) num=1 den=$1 ;; + 2) num=$1 den=$2 ;; + *) + printf >&2 '%s: Unexpected arguments\n' "$self" + exit 2 + ;; +esac + +# Numerator must be zero or greater, denominator must be 1 or greater +if [ "$((num >= 0 || den >= 1))" -ne 1 ] ; then + printf >&2 '%s: Illegal numerator/denominator %s\n' "$self" "$num" + exit 2 +fi + +# Perform the test; that's our exit value +seed=$(rnds) +test "$(rndi 1 "$den" "$seed")" -le "$num" |