Any way to edit a file on an external USB?

[journeyman]

Is there any way to edit a file on an external usb connected to the FGT? Viewing is fine:

fnsysctl more /usb/myfile.conf  # works fine

fnsysctl cat /usb/myfile.conf   # works fineEditing is less obvious. vi, sed and awk report they are not present with "can not find command xx". Redirecting output from ls to create a file on the usb also fails.

It would be of some use to be able to make small changes to a configuration file on a usb prior to restoring it.

[ede_pfau]

gate # fnsysctl df
fnsysctl cannot be executed when external USB disk is inserted.

on FOS v5.6.5  [&o]

[journeyman]

That's a pity. My tests were on 5.4.4 but there's not much point investigating a solution that won't work in 5.6.