Get Unique Values of a CSV Column Using Bash Command

Example input CSV file. The file is named transaction.csv

invoice_number,item_id,qty
#001,1,2
#001,2,2
#002,2,2
#003,1,2
#003,5,3
#004,2,2
#003,5,3
#005,2,2

The goal is to get the list of unique invoice_number

#001
#002
#003
#004
#005

Step

1. Run awk command split by comma (-F), then print the first column. awk -F ',' '{print $1}' transaction.csv
2. Add sorting with unique params sort -u. Use -r to get reverse order
3. Final command is awk -F ',' '{print $1}' transaction.csv | sort -u

Reference

• More detail about awk command http://tldp.org/LDP/abs/html/awk.html
• More detail about sort -u vs sort | uniq performance discussion at stackoverflow thread