[event-participant] Add help and printing option

Add a printing option to print the full list if input is empty.

Also add a help message.

diff --git a/event-participant b/event-participant
index a14e3aab6cd29067c0b17582064d94a2d4abf670..fccdd42ad697cedc6db468b73ca53547f052d7b8 100755 (executable)
--- a/event-participant
+++ b/event-participant
@@ -1,8 +1,29 @@
 #!/usr/bin/env bash
 
+HELP="
+Adds a particpant to an event.
+
+   event-participant [--help] [FILE]
+
+Participant and date added are read from email on standard input. The
+record is mantained in FILE. Most common is to leav FILE out, then the
+formermost record is reused.
+
+If input is empty, also list of particiants is printed.
+
+    echo | event-participant
+
+Help is this message.
+"
+
 CACHE="$HOME/.cache/${0##*/}/events.csv"
 HEADER="participant,date_att,date_cancel"
 
+if [[ "$1" == "--help" ]]; then
+    echo -e "$HELP" 1>&2
+    exit 0
+fi
+
 arg_event="$1"
 
 if [ -f "$CACHE" ]; then
@@ -43,3 +64,6 @@ n_t=$(cat "$event" | grep -v "$HEADER"| cut -d, -f2 | grep -v '^$' | wc -l)
 n_c=$(cat "$event" | grep -v "$HEADER"| cut -d, -f3 | grep -v '^$' | wc -l)
 n_p=$(( $n_t - $n_c ))
 echo -ne "At $event:\n   part: $n_p\n   canc: $n_c\n" 1>&2
+if [ -z "$info" ]; then
+    cat "$event" | tr ',' '\t'
+fi