Under a Linux shell, how can I change the creation time of all a folder's files to the current time?
Navigate to the folder in question, let's say, ~/Documents/myfiles.
This will change the modification time to whenever you executed that command.
Obviously you can make this more specific depending on your use case, e.g.
will only alter the modification time for files with the string '.doc' in their name.
In Linux, if you want to do some thing recursively in directory, or you want to apply some actions on files meeting some criterions，you should try
Touch all files in ~/Documents/myfiles (including files in sub directory)
As boehj said (in his comment) there is no creation time of a file... This is true for most of the filesystems, but on some modern filesystems (as ext4) the creation (or birth) time of a file is stored within the inode.
Therefore we can give a more correct answer scrupulously respecting the question title:
This will change the creation time (birth time) to the current time. This also updates the change time but keep unchanged the modification and access times.
For information, the change time is sometimes abbreviated as