Filename arrays in bash

Question

I want to make a filename array to use with ffmpeg under BASH.  For example there are six video files named video_1.h264, video_2.h264, video_3.h264, video_4.h264, video_5.h264 and video_6.h264.
I want to then concat them using ffmpeg
ffmpeg -i "concat:video_1.h264|video_2.h264|video_3.h264|video_4.h264|video_5.h264|video_6.h264" -c copy final.h264
Now I use the current code to do it with 1.h264, 2.h264, 3.h264, etc.
eval segments=\({1..$segments_variable}.h264\)
ifs=$IFS
IFS="|"
ffmpeg -i "concat:${segments[*]}" -c copy video.h264
$segments_variable is the amount of h264 files in the directory.
Now I want the code to automatically detect how many .h264 files in the directory and instead of just being number they have a title in them eg (video_1.h264)
I know how to create an array.  For example
arr=( $(ls $project_*.h264) )
segments_variable=$(echo ${#arr[@]})
$project would equal in this case "video" and segments_variable finds how many files are called video_*.h264.
Any ideas

Answer 1

rockin turtle wrote:
I think this will do what you want.  The files will be sorted lexically according to your locale (I believe).  If you don't want the file sorted in that order, I think you have to explicitly sort them as you wish.
#!/bin/bash
project="$1"
printf -v files "%s|" $project_*.h264
[[ $files =~ [*] ]] || ffmpeg -i "concat:${files%|}" -c copy output.h264
You don't really mean to check for "*" in the variable, but to avoid the case where the path expansion fails. Your check breaks when there is any "*" in the actual filenames. I suggest the `failglob` shopt for your purpose here.
I would also substitute `$project_*.h264` with `"$@"` to let the user pass the filenames, a trivial effort in exchange for much flexibility.