Bulk fixing photo and video dates

I have a lot of old digital photos with the correct date in the filename. But that date doesn’t match anymore with the file creation date. This can pose a big problem for a some photo library software out there, which depends on file creation date to correctly organize the photos (looking at you Google Photos).

Most of my photos generated from a digital camera or phone have dates somewhere in the file names, formatted something like:

IMG_20161226_115358.jpg
20180101_141437.jpg
VID_20171202_124719.mp4

There is a date in there. If only I could parse the date in each file, and manually set the creation date for each one accordingly…

Regular expressions to the rescue

The date portion of the filename can be represented by the following regular expression:

[0-9]{8}_[0-9]{6}

In simple terms it means match any 8 digits (yyyymmdd) followed by _, followed by any 6 digits (hhmmss).

Here’s a quick regexr playground to look at it in action.

Using this in a bash script could be done like so:

#!/bin/bash

filename="IMG_20161226_115358.jpg"

if [[ "$filename" =~ ([0-9]{8}_[0-9]{6}) ]]; then
  date_from_filename="${BASH_REMATCH[0]}"
  echo "$date_from_filename" # prints 20161226_115358
fi

We have the date formatted like yyyymmdd_hhmmss. But we need to convert it into a generic timestamp that can be used. To do that we can use the date utility to accept a predefined date format, and parse it into a proper system date.

date -jf "%Y%m%d_%H%M%S" "20161226_115358"
# Mon Dec 26 11:53:58 CET 2016

We can also output the parsed date into a format that can be used by the touch utility, to set the file creation date…

date -jf "%Y%m%d_%H%M%S" "20161226_115358" +"%Y%m%d%H%M%S"
# 20161226115358

Jumping ahead a few steps, we can assemble these building blocks into a full bash script that can:

1. Accept a directory of files
2. For each file, extract a date from the file name
3. Parse the date and reformat it to be used to modify the file creation date
4. Gracefully fail in any of these steps with a helpful message

#!/bin/bash

# Usage example: bash date-fixer.sh ~/Pictures/backup/

# Check if the correct number of arguments is provided
if [ "$#" -ne 1 ]; then
  echo "Usage: $0 <directory_path>"
  exit 1
fi

directory_path="$1"

# Check if the directory exists
if [ ! -d "$directory_path" ]; then
  echo "Error: Directory not found: $directory_path"
  exit 1
fi

# Loop through all files in the directory
for filename in "$directory_path"/*; do
  # Extract just the filename without the full path
  basename=$(basename "$filename")

   # Skip hidden files
  if [[ "$basename" == .* ]]; then
    continue
  fi

  # Extract date from filename
  if [[ "$basename" =~ ([0-9]{8}_[0-9]{6}) ]]; then
    date_from_filename="${BASH_REMATCH[0]}"
    echo "Date from filename: $date_from_filename"

    # Convert parsed date and time to timestamp
    timestamp=$(date -jf "%Y%m%d_%H%M%S" "$date_from_filename" +"%Y%m%d%H%M%S")

    # Check for valid timestamp
    if [[ ! "$timestamp" =~ ^[0-9]+$ ]]; then
      echo "Invalid timestamp for $filename: $timestamp"
      continue
    fi

    # Modify file's creation time
    touch -t "$timestamp" "$filename"
    echo "Modified creation time of $filename"
  else
    echo "Skipping file without date in filename: $file"
  fi
done