stgraber@castiana:~$ lxc export test --instance-only --optimized-storage --compression --project default
Error: Create backup: exec: "--project": executable file not found in $PATH
Which actually kinda makes sense as it parses:
arg0 => test (instance name)
instance-only => flag without value
optimized-storage => flag without value
compression => flag with value, taking the next arg as value (--project)
arg1 => default
So it effectively processes this request as: Export instance name with instance-only and optimized-storage set, using compression algorithm --target and export that to a file called default.
It’s a weird request but not an invalid one. Someone really odd could have a compressor tool on their system named --project