Question

For example suppose I have 1.csv, 2.csv, … , 20.csv. Is there a simple shell script where I can merge everything into merged.csv?

Answer 1

Use cat to concatenate them.

cat *.csv > merged.csv

As @sarnold points out this will concatenate them out of order. If that’s important, use his for loop suggestion, or this xargs pipeline:

ls *.csv | sort -n | xargs cat > merged.csv