Find which process is using a file on Mac

Use this command

lsof | grep <filename>

or

lsof <filepath>

To ignore case, use

lsof | grep -i <filename>

Run it as root if the process is owned by root,

sudo lsof | grep -i <filename>

Refs

• http://hints.macworld.com/article.php?story=20040121001144687
• http://forums.macrumors.com/showthread.php?t=462257