change folder modified date based on most recent file modified date in folder

Question

I have a number of project folders that all got their date modified set to the current date & time somehow, despite not having touched anything in the folders. I'm looking for a way to use either a batch applet or some other utility that will allow me to drop a folder/folders on it and have their date modified set to the date modified of the most recently modified file in the folder. Can anyone please tell me how I can do this?

In case it matters, I'm on OS X Mavericks 10.9.5. Thanks!

Answer 1

If you start a Terminal, and use stat you can get the modification times of all the files and their corresponding names, separated by a colon as follows:

stat -f "%m:%N" *

Sample Output

1476985161:1.png
1476985168:2.png
1476985178:3.png
1476985188:4.png
...
1476728459:Alpha.png
1476728459:AlphaEdges.png

You can now sort that and take the first line, and remove the timestamp so you have the name of the newest file:

stat -f "%m:%N" *png | sort -rn | head -1 | cut -f2 -d:

Sample Output

result.png

Now, you can put that in a variable, and use touch to set the modification times of all the other files to match its modification time:

newest=$(stat -f "%m:%N" *png | sort -rn | head -1 | cut -f2 -d:)
touch -r "$newest" *

So, if you wanted to be able to do that for any given directory name, you could make a little script in your HOME directory called setMod like this:

#!/bin/bash
# Check that exactly one parameter has been specified - the directory
if [ $# -eq 1 ]; then
   # Go to that directory or give up and die
   cd "$1" || exit 1
   # Get name of newest file
   newest=$(stat -f "%m:%N" * | sort -rn | head -1 | cut -f2 -d:)
   # Set modification times of all other files to match
   touch -r "$newest" *
fi

Then make that executable, just necessary one time, with:

chmod +x $HOME/setMod

Now, you can set the modification times of all files in /tmp/freddyFrog like this:

$HOME/setMod /tmp/freddyFrog

Or, if you prefer, you can call that from Applescript with a:

do shell script "$HOME/setMod " & nameOfDirectory

The nameOfDirectory will need to look Unix-y (like /Users/mark/tmp) rather than Apple-y (like Macintosh HD:Users:mark:tmp).