✨ Add optimize-pdfs shell function for optimizing PDF files

src/shell/bash_functions

@@ -114,6 +114,78 @@ h() {
 
 # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
+# Optimize PDF files.
+#
+# Usage examples:
+#
+#   optimize-pdfs path/to/some/directory path/to/some/file ...
+
+optimize-pdfs() (
+
+    # Check if the pdfcpu command-line tool is installed.
+
+    if ! command -v "pdfcpu" &> /dev/null; then
+        printf "\n%s\n\n" "pdfcpu command-line tool is not installed!"
+        exit
+    fi
+
+    # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
+    get-file-size() (
+        printf "%s" "$(wc -c < "$1")"
+    )
+
+    optimize-pdf() (
+        filePath="$(dirname "${1%/}")"
+        fileName="_$(printf "%s" "$(basename "$1")" | tr '[:upper:]' '[:lower:]')"
+
+        optimizedFilePath="$filePath/$fileName"
+
+        printf "* %s\n" "$1"
+
+        pdfcpu optimize "$1" "$optimizedFilePath" &> /dev/null
+
+        # If something went wrong (i.e. pdfcpu didn't create
+        # the optimized file or exited with a non-zero status)
+        # or the size of the optimized file is bigger than the
+        # original file, keep the original file.
+
+        if [ ! -f "$optimizedFilePath" ]; then
+            return
+        fi
+
+        # shellcheck disable=SC2181
+        if [ $? -ne 0 ] || \
+           [ "$(get-file-size "$1")" -le "$(get-file-size "$optimizedFilePath")" ];
+        then
+            rm -rf "$optimizedFilePath"
+            return
+        fi
+
+        # Otherwise, replace the original file with the optimized one.
+
+        mv -f "$optimizedFilePath" "$1" 1> /dev/null
+    )
+
+    #                     ┌─ Default to the current directory.
+    for filePath in "${@:-.}"; do
+        if [ -d "$filePath" ]; then
+            find "${filePath%/}" \
+                -depth 1 \
+                -name \*.pdf \
+                -print \
+                -type f \
+            | while read -r file; do
+                 optimize-pdf "$file"
+              done
+        elif [ -f "$filePath" ]; then
+             optimize-pdf "$filePath"
+        fi
+    done
+)
+
+# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
 # Rename media files.
 #
 # Rename the specified files so the filename is the file created date