diff --git a/README.md b/README.md
index f6cbcb4..fb62d3f 100644
--- a/README.md
+++ b/README.md
@@ -14,6 +14,8 @@ I’m coming across having to write the same shell script bits occasionally, and
 
 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
@@ -23,7 +25,7 @@ wait_for_url url<string> [iterations<int> duration<int>]
 Usage:
 
 ```shell
-source ./wait_for_url.sh
+. ./wait_for_url.sh
 
 # try 3 times, 1s apart
 wait_for_url http://127.0.0.1:5984
@@ -39,6 +41,8 @@ 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
@@ -48,7 +52,7 @@ wait_for_pid_exit pid<int> [iterations<int> duration<int>]
 Usage:
 
 ```shell
-source ./wait_for_pid_exit.sh
+. ./wait_for_pid_exit.sh
 
 # try 3 times, 1s apart
 wait_for_pid_exit 3618
@@ -74,7 +78,7 @@ Usage:
 
 ```shell
 
-source ./lib
+. ./lib
 
 # print message, then exit
 error_and_exit "this did not work"
@@ -98,17 +102,17 @@ assert_arg arg<any>
 Usage:
 
 ```shell
-source ./lib.sh
+. ./lib.sh
 
 
 # fail if arg is missing
-function my_fun () {
+my_fun () {
 	assert_arg $1 && url=$1 || error_and_exit "error 'url' missing"
 	# now $url is available
 }
 
 # set arg to default value if missing
-function my_fun () {
+my_fun () {
 	assert_arg $1 && iterations=$1 || iterations=5
 	# now $iterations is available
 }
diff --git a/lib.sh b/lib.sh
index d9b8c62..8064f9e 100644
--- a/lib.sh
+++ b/lib.sh
@@ -1,22 +1,22 @@
 
-function debug () {
+debug () {
 	if [ -n "$DEBUG" ]; then
 		echo "$1"
 	fi
 }
 
-function debug_inline () {
+debug_inline () {
 	if [ -n "$DEBUG" ]; then
 		printf "$1"
 	fi
 }
 
-function error_and_exit () {
+error_and_exit () {
 	echo $1 || "error"
 	exit 1
 }
 
-function assert_arg () {
+assert_arg () {
 	arg=$1
 
 	if [ -z "$arg" ]; then
diff --git a/test.sh b/test.sh
index 371e08a..e4d6734 100755
--- a/test.sh
+++ b/test.sh
@@ -19,7 +19,7 @@
 # echo
 
 
-source ./wait_for_pid_exit.sh
+. ./wait_for_pid_exit.sh
 
 echo test5
 (wait_for_pid_exit 45591 4 17)
diff --git a/wait_for_pid_exit.sh b/wait_for_pid_exit.sh
index 66f194c..e2e941e 100644
--- a/wait_for_pid_exit.sh
+++ b/wait_for_pid_exit.sh
@@ -1,7 +1,7 @@
 
-source ./lib.sh
+. ./lib.sh
 
-function wait_for_pid_exit () {
+wait_for_pid_exit () {
 	assert_arg "$1" && pid="$1" || error_and_exit "pid not provided, exiting"
 	assert_arg "$2" && iterations="$2" || iterations=3
 	assert_arg "$3" && duration="$3" || duration=1
diff --git a/wait_for_url.sh b/wait_for_url.sh
index 8c2f95a..4e30a6d 100644
--- a/wait_for_url.sh
+++ b/wait_for_url.sh
@@ -1,7 +1,7 @@
 
-source ./lib.sh
+. ./lib.sh
 
-function wait_for_url () {
+wait_for_url () {
 	assert_arg "$1" && url="$1" || error_and_exit "url not provided, exiting"
 	assert_arg "$2" && iterations="$2" || iterations=3
 	assert_arg "$3" && duration="$3" || duration=1