JPEG compression script

jpg4web.bash

@@ -0,0 +1,37 @@
+#!/bin/bash
+
+# 800px is the width of the content on my site
+WIDTH=800
+
+set -o errexit
+set -o nounset
+set -o pipefail
+
+show_usage() {
+    echo "Usage: jpg4web.bash [imagefile]"
+    exit 1
+}
+
+# Check argument count
+if [ "$#" -ne 1 ]; then
+    show_usage
+fi
+
+# Check that it ends in .jpg
+if [[ "$1" != *.jpg ]]; then
+    echo "Argument [imagefile] must end in .jpg"
+    show_usage
+fi
+
+# Check that relevant commands exist
+if ! command -v mogrify > /dev/null; then
+    echo "Command magick not found. Exiting..."
+fi
+if ! command -v jpegoptim > /dev/null; then
+    echo "Command jpegoptim not found. Exiting..."
+fi
+
+cp "$1" "$1.bak"
+mogrify -resize "$WIDTH" "$1"
+jpegoptim "$1"
+