Paste is a tool that allows to merge files together.
Merge files
To merge files in parallel, you can run the following command:
paste <file1> <file2>
Merge files with a specific delimiter
The default delimiter is Tab but it is possible to modify it:
paste -d "|" [files...]
Note that if you specified multiple delimiters, paste will use it in a circular buffer and increment after each delimitation.
Merge files in serial
The default option is to merge files in a parallel way. If you want to merge file using a serial way (row instead of column), it can be achieve with the -s flag:
paste -s [files]