docs(usage): add more documentation

timeout

@@ -1,8 +1,33 @@
 #!/bin/sh
 
 usage() {
-	printf "Usage: %s [-t TIMEOUT] [-c COMMAND]\n\n" "$0"
-	printf "TIMEOUT and COMMAND can be set as env vars.\n"
+    printf "Usage: %s [-v] [-h] [-t TIMEOUT] [-c COMMAND]\n\n" "$0"
+}
+
+help() {
+    cat << EOH
+ SYNOPSIS
+    $0 [-v] [-h] [-t TIMEOUT] [-c COMMAND]
+
+ DESCRIPTION
+
+    \`Timeout\` executes a command until the timeout is over.
+    When the command is finished before the timeout then the exit code is \`0\` else it's \`1\`.
+
+ OPTIONS
+
+    -h    Show this help
+
+    -v    Display  the command output (stderr)
+
+    -c COMMAND
+          The command to execute
+          \`COMMAND=... $0\` works to.
+
+    -t TIMEOUT
+          The timeout in seconds (default: 10)
+          \`TIMEOUT=... $0\` works to.
+EOH
 }
 
 on_interrupt() {
@@ -45,7 +70,7 @@ check_pid() {
 main() {
     while getopts "ht:c:v" option; do
         case "${option}" in
-			h) usage; exit 0;;
+            h) help; exit 0;;
             t) TIMEOUT="$OPTARG";;
             c) COMMAND="$OPTARG";;
             v) VERBOSE=1;;