I am trying to update my BIOS:

$ sudo dmidecode -s bios-version
2.1.2 

With a newer one: 2.6.0. I went to this page Dell Precision System BIOS, 2.6.0

After downloading the file WS390-020600.BIN, here is what it states:

$ ./WS390-020600.BIN --help
Usage: WS390-020600.BIN [options]
Options:
  --help                  Print this text.
  --version               Print package versions.
If no options, update the BIOS.

and

$ ./WS390-020600.BIN --version
Dell BIOS Update Installer 1.2
Copyright 2006 Dell Inc. All Rights Reserved.

./WS390-020600.BIN: 60: ./WS390-020600.BIN: ./flash: not found

Does anyone knows where this flash command can be found ?

Update: it looks like this is a self-extracting archive (need bash as per comment in header).

$ head -30 WS390-020600.BIN
[...]
Extract()
{
    tail -n +`awk '/^__ARC__/ { print NR + 1; exit 0; }' $0` $0 | gzip -cd >$_PRG

So the flash command should have been auto-generated, however the above command does not appear to be running as original author intended. I do not see anything wrong with the command though.