bin/untill: Add support for "-m MAX" option

1 files changed, 14 insertions, 6 deletions

diff --git a/bin/untill b/bin/untill
index 030f921..738b5bb 100755
--- a/bin/untill
+++ b/bin/untill
@@ -4,7 +4,7 @@ set -eu
 usage() {
 	cat <<-'EOF'
 		Usage:
-		  until [-n SECONDS] -- COMMAND...
+		  until [-m MAX] [-n SECONDS] -- COMMAND...
 		  until -h
 	EOF
 }
@@ -15,11 +15,12 @@ help() {
 		Options:
 		  -n SECONDS    the amount of seconds to sleep between
 				attempts (default: 5)
+		  -m MAX        the maximum number of attempts (default: unlimited)
 		  -h, --help    show this message
 
 
-		Runs COMMAND until it eventually succeeds.  Sleep SECONDS
-		between attempts.
+		Runs COMMAND until it eventually succeeds, trying atmost MAX
+		times.  Sleep SECONDS between attempts.
 
 
 		Examples:
@@ -29,10 +30,10 @@ help() {
 		    $ until guix home build home.scm
 
 
-		  Try to build until a new version is successfull,
+		  Try atmost 10 timex to build until a new version is successfull,
 		  waiting 30 seconds between attempts:
 
-		    $ until -n 30 -- x git pull AND make
+		    $ until -m 10 -n 30 -- x git pull AND make
 	EOF
 }
 
@@ -53,8 +54,11 @@ for flag in "$@"; do
 done
 
 _SECONDS=5
-while getopts 'n:h' flag; do
+while getopts 'm:n:h' flag; do
 	case "$flag" in
+		m)
+			MAX="$OPTARG"
+			;;
 		n)
 			_SECONDS="$OPTARG"
 			;;
@@ -79,5 +83,9 @@ while true; do
 	if "$@"; then
 		break
 	fi
+	if [ -n "${MAX:-}" ] && [ "$ATTEMPT" -gt "$MAX" ]; then
+		printf 'Maximum number of attempts reached: %s.\n' "$MAX" >&2
+		exit 1
+	fi
 	sleep "$_SECONDS"
 done