Last Updated: 2024-03-05
This is a general purpose trick to stop programs from printing out filenames given to them as arguments: feed the program its data via redirection instead of via an argument file name.
wc -l oxnotes.log prints
134344444 oxnotes.log, the extra filename
being annoying for feeding the line count into arithmetical subexpressions.
wc -l < oxnotes.log just gives the number. Presumably
wc never received
a filename argument here, therefore cannot possibly print it.