Add example task

Justfile

@@ -7,7 +7,7 @@ _curl day url *args:
 day := `date +'%d'`
 new day=day:
     #!/usr/bin/env bash
-    set -euxo pipefail
+    set -euo pipefail
     mkdir day-{{day}}/
     just _curl {{day}} input -o day-{{day}}/input
     cat > day-{{day}}/main.raku <<'MAIN'
@@ -33,6 +33,7 @@ run day=day:
 
 test day=day:
     #!/usr/bin/env bash
+    set -euo pipefail
     for f in day-{{day}}/example-*.in; do
         tput setaf 2; echo $'\t'$f; tput setaf 7;
         raku day-{{day}}/main.raku $f
@@ -40,3 +41,9 @@ test day=day:
 
 watch day=day:
     watchexec just test {{day}}
+
+example day=day:
+    #!/usr/bin/env bash
+    set -euo pipefail
+    for f in day-{{day}}/example-{1..9}.in; do test -f $f || break; done
+    cat > $f