Examples: add moulti-needle-haystack.bash.

examples/README.md

@@ -16,6 +16,7 @@ Descriptions:
 |------------------|-------|-------|---------|--------|---------|
 | debian-upgrade   | ⚠️  [1]|  ❌   |   ❌    |   ❌   |   ❌    |
 | many-buttons     | ✅    |  ✅   |   ✅    |   ✅   |   ✅    |
+| needle-haystack  | ✅    |  ✅   |   ✅    |   ✅   |   ✅    |
 | pass-concurrency | ✅    |  ✅   |   ✅    |   ✅   |   ✅    |
 | progressbar      | ✅    |  ✅   |   ✅    |   ✅   |   ✅    |
 | python-checks    | ✅    |  ✅   |   ✅    |   ✅   |   ✅    |

examples/moulti-needle-haystack.bash

@@ -0,0 +1,51 @@
+#!/usr/bin/env bash
+
+# Force bash to populate $LINES:
+shopt -s checkwinsize
+:|:
+export LINES
+
+export MOULTI_INSTANCE='needle-haystack'
+[ "${MOULTI_RUN}" ] || exec moulti run -- "$0" "$@"
+
+set -e
+source moulti-functions.bash
+moulti_check_requirements 'seq'
+
+factor="${FACTOR:-1000}"
+((before=11*factor))
+((middle=11*factor))
+((after=11*factor))
+((last_line=before+middle+after))
+
+haystack_x1=' haystack'
+needle_x1=' needle  '
+printf -v haystack_x10 "%.0s${haystack_x1}" {1..10}
+haystack_format="%6.f${haystack_x10}${haystack_x10}${haystack_x10}${haystack_x1}"
+needle_format="%6d${haystack_x10}${haystack_x10}${needle_x1}${haystack_x10}\n"
+
+function needle_in_haystack {
+	local needle_line_number
+	((needle_line_number=before+RANDOM%middle))
+	seq -f "${haystack_format}" 1 "${needle_line_number}"
+	((needle_line_number++))
+	# shellcheck disable=SC2059
+	printf "${needle_format}" "${needle_line_number}"
+	((needle_line_number++))
+	seq -f "${haystack_format}" "${needle_line_number}" "${last_line}"
+}
+
+lines="${LINES:-30}"
+((lines=(lines-3)/2))
+
+moulti set --title='Find needles inside the haystacks'
+for i in {1..5}; do
+	moulti step add "haystack${i}" --title="Haystack #${i}" --max-height="${lines}"
+done
+needle_in_haystack | moulti pass "haystack1" &
+needle_in_haystack | moulti pass "haystack2" &
+wait
+needle_in_haystack | moulti pass "haystack3" &
+needle_in_haystack | moulti pass "haystack4" &
+wait
+needle_in_haystack | moulti pass "haystack5"