Shell or mv eats a period?

[Ian Lepore]

On Tue, 2016-06-14 at 08:38 -0700, bob prohaska wrote:
> During a recent update of freebsd-arm on an rpi2 I happened to type
> root at ns1:/boot/msdos # ls
> bootcode.bin	fixup_cd.dat	readme		start_c
> d.elf	ubldr
> config.txt	fixup_x.dat	rpi2.dtb	start_x.elf
> fixup.dat	licence.bro	start.elf	u-boot.bin
> 
> To prepare for upgrading from r494499, I then typed
> 
> root at ns1:/boot/msdos # mv rpi2.dtb rpi2.dtb.old
> 
> root at ns1:/boot/msdos # ls
> bootcode.bin	fixup_cd.dat	readme		start_c
> d.elf	ubldr
> config.txt	fixup_x.dat	rpi2dtb.old	start_x.elf
> fixup.dat	licence.bro	start.elf	u-boot.bin
> 
> Note that the renamed file has lost the first dot. Next, the new file
> was copied into position:
> 
> root at ns1:/boot/msdos # cp /boot/dtb/rpi2.dtb /boot/msdos
> root at ns1:/boot/msdos # ls
> bootcode.bin	fixup_cd.dat	readme		start.e
> lf	u-boot.bin
> config.txt	fixup_x.dat	rpi2.dtb	start_cd.elf	
> ubldr
> fixup.dat	licence.bro	rpi2dtb.old	start_x.elf
> root at ns1:/boot/msdos #
> 
> It's happened twice so far, so it's unlikely to be a wetware error 8
> -)
> Can anybody tell me what happened?
> 
> thanks for reading,
> 
> bob prohaska

A FAT filesystem enforces that there is only a single dot in a
filename.  Welcome to 1983.

-- Ian