Merge multiple text files into one file
Step 1: check the last line of text file is newline[1]
- tail -c 1 file.txt on Linux
. Parameter "-c number: The location is number bytes." quoted from the commands manual. If the last line is newline, returned result will be empty. 
How to check multiple files? - (optional) If the last line is not newline, you may add the new line manually. See details on bash - How to add a newline to the end of a file? - Unix & Linux Stack Exchange
Step 2: Merge the content
- copy *.txt > bundle.txt or copy file1.txt file2.txt > bundle.txt on Win
- cat *.txt > bundle.txt or cat file1.txt file2.txt > bundle.txt on Linux [2][3]
Step 3: (optional) Remove the duplicated lines
- sort -us -o bundle_unique.txt bundle.txt[4] OS: Linux , cygwin of Win "-u means Unique keys; -s means stable sort; -o means output" quoted from sort manual.
- ↑ eof - Linux - check if there is a newline at the end of a file - Stack Overflow
- ↑ Terminal 101: Join Multiple Files Together with Cat
- ↑ How to merge all (text) files in a directory into one? - Unix & Linux Stack Exchange
- ↑ linux - How to remove duplicate lines in a large multi-GB textfile? - Unix & Linux Stack Exchange