Work with text files

The post describes basic tricks to deal with text files in Linux. It's useful when you process large lists of records. Concatenate files and keep the new line at the end of each file:

sed '$a\' input_files* > output_file

Check the number of unique lines in a file:

uniq -u file_name | wc -l

Change the format of the new line: Linux to Windows

unix2dos

Windows to Linux

dos2unix

Or in case of permission issues with the temporary file:

dos2unix -n test_file tmp_file
mv -f tmp_file test_file

Some additional info is available here: https://access.redhat.com/solutions/3168671