UNIX for Dummies Questions & Answers

Hi all,

I wish to know about a simple concept of mv command in UNIX. Is moving a file to a different directory takes longer than renaming it in the same direcotry using the mv command?

The scenerio is that I have to transfer a file from one directory to a location which is regularly scanned by some "program" for the file. This "program" moves the file to some other system. Now if the input file is huge, the "program" may transfer the file before the whole file is moved to this location.

So I decided to move the file with a different name to the second location. Once this operation is complete then I would rename the file to the original name so that the "program" can transfer the file.

My query is that whether the renaming would take same time as move operation? If so, then my approach may not work......Please suggest......

Thanks in advance.

The mv command changes the pointer to the file not the file itself. However, if the destination is on another file system (NFS mount are included here) a copy operation occurs first.

In other words, if you are moving a file from one file system to another, the file is actually copied. If you are moving the file within the same filesystem, the pointer to the file is changed but the data stays in place.

HTH

Hi, on unix systems you rename files by using the command mv. A mv within the same filesystem is instantanious and boils down to a rename. A mv to a different filesystem is like a copy operation followed by a remove.

A move to a different directory should take just as long as a move in the same directory as long as both directories are on the same filesystem.

A "mv" within the same mounted filesystem just changes the name entry for that inode and is very quick. The inode number does not change and the data does not move.

A "mv" across mounted filesystem boundaries will physically copy the file.