feat: exorcise bashisms

README.md

@@ -4,6 +4,8 @@ I’m coming across having to write the same shell script bits occasionally, and
 
 This is a *slowly* growing collection of hopefully useful and reusable shell functions and patterns.
 
+Currently tested in macOS only.
+
 Copyright (c) 2022 Jan Lehnardt <jan@apache.org>, MIT licensed
 
 ## Goals
@@ -29,8 +31,6 @@ This section documents reusable functions for your scripts.
 
 Wait for a particular URL to be available using `curl`. Wait `$duration` seconds between attempts, try `$iterations` times. Defaults to `1` seconds and `3` times.
 
-Requires `bash`.
-
 Signature:
 
 ```shell
@@ -56,8 +56,6 @@ wait_for_url http://127.0.0.1:5984 5 3
 
 Wait for a particular PID to exit. Wait `$duration` seconds between attempts, try `$iterations` times. Defaults to `1` seconds and `3` times.
 
-Requires `bash`.
-
 Signature:
 
 ```shell

wait_for_pid_exit.sh

@@ -14,12 +14,12 @@ wait_for_pid_exit () {
 	debug_inline "waiting for $pid to exit "
 	until ( ! ps ax | grep $pid | grep -v grep > /dev/null); do
 		if [ $waiting -eq $iterations ]; then
-			let after=$duration*iterations
+			after=`expr $duration \* $iterations`
 			debug_inline "failed, $pid still running after $after seconds\n"
 			return 1
 		fi
 		debug_inline .
-		let waiting=waiting+1
+		waiting=`expr $waiting + 1`
 		sleep $duration
 	done
 	debug_inline " succeeded\n"

wait_for_url.sh

@@ -17,12 +17,12 @@ wait_for_url () {
 	debug_inline "waiting for $url "
 	until ($cmd); do
 		if [ $waiting -eq $iterations ]; then
-			let after=$duration*iterations
+			after=`expr $duration \* $iterations`
 			debug_inline "failed, $url can not be reached after $after seconds\n"
 			return 1
 		fi
 		debug_inline .
-		let waiting=waiting+1
+		waiting=`expr $waiting + 1`
 		sleep $duration
 	done
 	debug_inline " succeeded\n"