Unexpected inconsistency; Run fsck manually (initramfs)

I have read responses to similar questions, but I am still stuck. When trying to boot, I get the following message:

 /dev/sda5 contains a file system with errors, check forced.
Inodes that were part of a corrupted orphan linked list is found
 /dev/sda5: UNEXPECTED INCONSISTANCY; RUN fsck MANUALLY (i.e., without -a or -p options)
fsck exited with status code 4
The root filesystem on /dev/sda5 requires a manual fsck
BusyBox v1.221 (ubuntu 1:1.22.0-15 ubuntu1) built in shell (Ash)

(initramfs)

Earlier responses indicate I should enter sudo fsck/dev/sda5

However, when I enter that, I get:

/bin/sh: sudo not found.

If enter simply fsck/dev/sda5, then I get
/bin/sh: fsck/dev/sda5 not found.

And then I am back at (initramfs)

Since I can't boot up, I have no access to a terminal.

How do I proceed?

Thanks for your help

I have a dual boot arrangement