If extracting with GNU tar with an explicit list of files like this:
tar xf archive.tar file_a file_b file_c
what is the behavior if file_b is missing (i.e. archive.tar only contains file_a and file_c)? Are file_a and file_c guaranteed to be extracted?
Yes, the other files will be extracted.
Each file is extracted when it is encountered in the tar file. When tar finds the files file_a and file_c, it has not way to determine whether there will be a file_b after that or not. Remember, the name tar is derived from tape archive, it reads the archive from start to end, without seeking.
