Add msi.

Formula/libmseed.rb

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+class Libmseed < Formula
+  desc "Library for the miniSEED data format"
+  homepage "https://iris-edu.github.io/libmseed"
+  url "https://github.com/iris-edu/libmseed/archive/refs/tags/v2.19.8.tar.gz"
+  sha256 "10ac972cb4e76c8d6aa27bf9f56fc59d1922991477d9ddefd375b89dba9e93f6"
+  license "Apache-2.0"
+
+  def install
+    system "make", "install", "PREFIX=#{prefix}"
+  end
+end

Formula/msi.rb

@@ -0,0 +1,28 @@
+class Msi < Formula
+  desc "Print details of data in miniSEED format"
+  homepage "https://github.com/iris-edu/msi"
+  url "https://github.com/iris-edu/msi/archive/refs/tags/v3.8.tar.gz"
+  sha256 "e1018936832346868307a9934d82083e77894c0e356aab03e0a7e0146bbb6fec"
+  license "GPL-3.0"
+
+  depends_on "libmseed"
+
+  def install
+    rm_r "libmseed"
+
+    cd "src" do
+      inreplace "Makefile" do |s|
+        s.gsub! "-I../libmseed", ""
+        s.gsub! "-L../libmseed", ""
+      end
+
+      system "make"
+    end
+
+    bin.install "msi"
+  end
+
+  test do
+    system "msi", "-h"
+  end
+end