Hello guys!
I need help converting two scripts I use on windows to be able to use them on linux, I am new to linux and all of my attempts have failed.

1.
Code:
for %%a in (*.mkv) do mkvmerge -o "output\%%~a" --subtitle-tracks ara --default-track 3 "%%~a"
2.

Code:
FORFILES /M "*.mkv" /c "cmd /c ffmpeg -ss 5.5 -i  ^"@file^" -c copy -map 0 ^"done\\@file^""
Thanks in advance!