How does FFmpeg concat videos and output same file prefix - bash

Question

I have a lot of videos cut into three parts, and I want to concat them.
I now have the following bash to output videos in the folder to a file named mergedVideo.mp4.
for f in *.mp4 ; do echo file \'$f\' >> fileList.txt;done
ffmpeg -f concat -safe 0 -i fileList.txt -c copy mergedVideo.mp4
All my input files are like Something part1.mp4, Something part2.mp4, Something part3.mp4
What I want is to output a file named Something.mp4
It is possible?
How can I modify my bash to achieve that~?

Answer 1

Would you please try the following:
#!/bin/bash
pat="^([^[:space:]]+)[[:space:]]*part[[:digit:]]+\.mp4$"
for f in *.mp4; do
echo file \'$f\' >> fileList.txt
[[ $f =~ $pat ]] && mergedvideo="${BASH_REMATCH[1]}.mp4"
done
ffmpeg -f concat -safe 0 -i fileList.txt -c copy "$mergedvideo"
Explanation of the regex $pat:
^([^[:space:]]+) matches a non-space substring from the beginning of the
string $f and is assigned to the shell variable BASH_REMATCH[1].
As for the provided example filenames, BASH_REMATCH[1] will be assigned to Something.
[[:space:]]* matches a zero or more whitespace(s).
part[[:digit:]]+ matches a string "part" followed by digit(s).
\.mp4 matches the suffix.
[Alternative]
If you are familiar with sed as well, the following may be more readable and maintainable:
mergedvideo=$(sed -E 's/[[:space:]]*part[[:digit:]]+//' <<< "$f")

Answer 2

I extend tshiono's answer to be able to manipulate all the files in the same folders (just like Marinos An mentioned, the idea is to merge files with the same prefix)
Cases like a folder with the following files:
Monday Blue part1.mp4
Monday Blue part2.mp4
Tuesday.mp4
Wednesday part1.mp4
Wednesday part2.mp4
Wednesday part3.mp4
Expected Output:
Monday Blue.mp4
Tuesday.mp4
Wednesday.mp4
#!/bin/bash
pat="^(.+)[[:space:]]+part[[:digit:]]+\.mp4$"
for f in *.mp4; do
if [[ $f =~ $pat ]]; then
echo file \'$f\' >> "${BASH_REMATCH[1]}.txt"
fi
done
for f in *.txt; do
ffmpeg -f concat -safe 0 -i "${f%%.*}.txt" -c copy "${f%%.*}.mp4"
done