[picsort] / rename-to-date

#!/usr/bin/env bash
set -euo pipefail
mv_command=mv
skip_duplicates=true
while getopts l opt;do
 case $opt in
  l)    mv_command=ln;;
 esac
done
shift "$((OPTIND - 1))"

for f; do
  if [[ ! -e "$f" ]];then
    echo "Input file \"$f\" does not exist." >&2
    continue
  fi
  extension=${f##*.}
  new_name="$(find "$f" -printf "%TY-%Tm-%Td %TT %TZ").$extension"
  while [[ -e "$new_name" ]];do
    if $skip_duplicates;then
      if [[ "$(find "$f" -printf '%i')" == "$(find "$new_name" -printf '%i')" ]];then
        echo "Skipping $f: it is already $new_name (same inode)"
      fi
      if cmp "$f" "$new_name";then
        echo "Skipping $f: it is already $new_name"
        continue 2
      fi
    fi
    fields=( $new_name )
    t=${fields[1]#*.}
    if (( ${#t} != 10 ));then
      echo "Expected $t (from $new_name) to be 10 characters" >&2
      exit 1
    fi
    t=$(printf "%010d" $(( $(sed 's/^0*//' <<< "$t") + 1 )) )
    new_name="${fields[0]} ${fields[1]%.*}.$t ${fields[2]}"
  done
  $mv_command -vi "$f" "$new_name"
done