There's some back story to this, so bare with me for a bit.
In an attempt the create a free space partition for Ubuntu without using the disk utility applicatition I booted into recovery mode and tested
diskutil partitionDisk /dev/disk0 GPT free Linux 100G
just to see if I could create a free space partition to install Ubuntu on.
1st, I am not even all that sure if that was the proper syntax to use, although the command seemed to work, but when I tried to boot back into macos, I got the folder with a question mark picture.
I went back into recovery mode and found that the volume
/dev/disk0s2 was giving an error.
so i removed the volume /dev/disk0s2.
gpt remove -i 2 disk0
gpt -r show disk0
I am was left with
# gpt -r show disk0 start size index contents 0 1 PMBR 1 1 Pri GPT header 2 32 Pri GPT table 34 6 40 409600 1 GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B 409640 1953115495 1953115495 32 Sec GPT table 1953115167 1 Sec GPT header
(there is no C&P in recovery mode)
then tried to add the partition back since I'm sure of whatfile system I've been using.
gpt add -i 2 -b 409640 -s 195311549 -t 7C3457EF-0000-11AA-AA11-00306543ECAC disk0
it is an Apple APFS partition.
but even with that, when I try to verify the volume
diskutil verifyVolume disk0s2
i get the error
starting file system verification for disk0s2: Unrecognized file system (-69846)
Any help in repairing my volume and the proper syntax for partitioning free space would help.
/dev/disk0 (internal, physical): #: TYPE NAME SIZE IDENTIFIER 0: GUID_paritition_scheme *1.0 TB disk0 1: EFI EFI 209.7 MB disk0s1 2: 7C3457EF-0000-11AA-AA11-00306543ECAC 1000.0 GB disk0s2
but I still cannot boot into macOS without seeing the question mark folder.
After David Anderson's explanation of my blunder, and me backtracking as a result of Klanomath's reply of what the proper command should have been...
gpt -r show disk0
now shows up as follows
# gpt -r show disk0
start size index contents
0 1 PMBR
1 1 Pri GPT header
2 32 Pri GPT table
40 409600 1 GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B
409640 1953115488 2 GPT part - 7C3457EF-0000-11AA-AA11-00306543ECAC
1953525135 32 Sec GPT table 1953525167 1 Sec GPT header