install.sh: Make bash 3 compatible

[why]
Vanilla MacOS has just some very old bash 3 installed by default. People
might want to use the install.sh, but not install a newer bash (via
Homebrew for example).

[how]
The `nerdfonts_dirs` array is replaced by a normal bash variable (string)
where the directories are '/' separated. Because there are never
subdirectories in the list but only direct children of 'patched-fonts/'
it is possible to use slash as unique and out-of-band separator.

The `fonts` array is replaced by a function that delivers the list of
files in null-byte separated form. That means we can not manipulate the
list and thus the duplicate checking is dropped. As we do not have any
font in both formats (anymore) it will never happen anyhow.
Dropping the duplicates check also removes the extension preference
option functionality. We keep the now defunct option, though.

Signed-off-by: Fini Jastrow <ulf.fini.jastrow@desy.de>

install.sh

@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 # Install Nerd Fonts
-__ScriptVersion="0.8"
+__ScriptVersion="0.9"
 
 # Default values for option variables:
 quiet=false
@@ -113,11 +113,10 @@ version
 # Set source and target directories, default: all fonts
 sd="$( cd -- "$(dirname "$0")" >/dev/null 2>&1 || exit ; pwd -P )"
 nerdfonts_root_dir="${sd}/patched-fonts"
-nerdfonts_dirs=("$nerdfonts_root_dir")
 
 # Accept font / directory names, to avoid installing all fonts
 if [ -n "$*" ]; then
-  nerdfonts_dirs=()
+  nerdfonts_dirs=
   for font in "${@}"; do
     if [ -n "$font" ]; then
       # Ensure that directory exists, and offer suggestions if not
@@ -126,10 +125,14 @@ if [ -n "$*" ]; then
         find "$nerdfonts_root_dir" -mindepth 1 -maxdepth 1 -type d -printf "%f\\n" | sort
         exit 255
       fi
-      nerdfonts_dirs=( "${nerdfonts_dirs[@]}" "$nerdfonts_root_dir/$font" )
+      nerdfonts_dirs+="${font}/"
     fi
   done
+else
+  nerdfonts_dirs=$(cd "${nerdfonts_root_dir}" && find . -mindepth 1 -maxdepth 1 -type d -printf "%f/")
 fi
+# nerdfonts_dirs contains a '/' separated list of directories directly
+# under nerdfonts_root_dir to look at (it needs to end in '/')
 
 # Which Nerd Font variant
 if [ "$variant" = "M" ]; then
@@ -140,37 +143,13 @@ else
   find_filter="-not -name '*NerdFontMono*' -and -not -name '*NerdFontPropo*' -and -name '*NerdFont*'"
 fi
 
-# Find all the font files and store in array
-files=()
-for dir in "${nerdfonts_dirs[@]}"; do
-  while IFS=  read -r -d $'\0'; do
-    files+=("$REPLY")
-  done < <(echo "${find_filter} -print0" | xargs -- find "${dir}" -iname '*.[ot]tf' -type f)
-done
-
-#
-# Remove duplicates (i.e. when both otf and ttf version present)
-#
-
-# Get list of file names without extensions
-files_dedup=( "${files[@]}" )
-for i in "${!files_dedup[@]}"; do
-  files_dedup[i]="${files_dedup[$i]%.*}"
-done
-
-# Remove duplicates
-for i in "${!files_dedup[@]}"; do
-  for j in "${!files_dedup[@]}"; do
-    [ "$i" = "$j" ] && continue
-    if [ "${files_dedup[$i]}" = "${files_dedup[$j]}" ]; then
-      ext="${files[$i]##*.}"
-      # Only remove if the extension is the one we don’t want
-      if [ "$ext" != "$extension" ]; then
-        unset "${files[$i]}"
-      fi
-    fi
-  done
-done
+collect_files() {
+  # Find all the font files, return \0 separated list
+  local find_opts="${find_filter} -print0"
+  while IFS= read -d / -r dir; do
+    xargs -- find "${nerdfonts_root_dir}/${dir}" -iname '*.[ot]tf' -type f <<< "$find_opts"
+  done <<< "${nerdfonts_dirs}"
+}
 
 # Get target root directory
 if [[ $(uname) == 'Darwin' ]]; then
@@ -196,7 +175,7 @@ else
   font_dir="${usr_font_dir}"
 fi
 
-if [ "${#files[@]}" -eq 0 ]; then
+if [ -z "$(collect_files | tr -d '\0')" ]; then
   echo "Did not find any fonts to install"
   exit 1
 fi
@@ -216,22 +195,22 @@ prepare_dirs() {
 case $mode in
 
   list)
-    for file in "${files[@]}"; do
+    while IFS= read -d $'\0' -r file; do
       file=$(basename "$file")
       echo "$font_dir/${file#"$nerdfonts_root_dir"/}"
-    done
+    done < <(collect_files)
     exit 0
     ;;
 
   copy)
     prepare_dirs
-    [ "$quiet" = false ] && cp -fv "${files[@]}" "$font_dir"
-    [ "$quiet" = true ] && cp -f "${files[@]}" "$font_dir"
+    [ "$quiet" = false ] && (collect_files | xargs --null -- cp -fv -T "$font_dir")
+    [ "$quiet" = true ] && (collect_files | xargs --null -- cp -f  -T "$font_dir")
     ;;
   link)
     prepare_dirs
-    [ "$quiet" = false ] && ln -sfv "${files[@]}" "$font_dir"
-    [ "$quiet" = true ] && ln -sf "${files[@]}" "$font_dir"
+    [ "$quiet" = false ] && (collect_files | xargs --null -- ln -sfv -t "$font_dir")
+    [ "$quiet" = true ] && (collect_files | xargs --null -- ln -sf -t "$font_dir")
     ;;
 
   remove)