Bash Sort Lines

What Is sort?

sort reads every line of its input, orders them, and prints the result; by default it compares lines as plain text, character by character, in ASCII order. The examples below skip the header of team.csv with tail -n +2 so only the seven data rows are sorted.

$ tail -n +2 team.csv | sort
Alice Johnson,Engineering,29,85000
Bob Smith,Marketing,34,62000
David Lee,Sales,26,54000
Eve Davis,Marketing,38,71000
Frank Miller,Engineering,45,110000
carol white,engineering,41,95000
grace hopper,Sales,31,67000

Numeric Sort with -n

Notice that carol and grace, whose names start with lowercase letters, sorted after every capitalized name above; in ASCII, uppercase letters come before lowercase ones. That same text comparison also breaks numbers, since the string 9 is considered greater than 54000 character by character. -n tells sort to compare fields as actual numbers, and -k combined with -t picks which delimited field to sort by, here the salary in column four.

$ tail -n +2 team.csv | sort -t',' -k4 -n
David Lee,Sales,26,54000
Bob Smith,Marketing,34,62000
grace hopper,Sales,31,67000
Eve Davis,Marketing,38,71000
Alice Johnson,Engineering,29,85000
carol white,engineering,41,95000
Frank Miller,Engineering,45,110000

Reverse Order with -r and Deduplicating with -u

-r reverses whichever ordering is already active, numeric or alphabetical, so pairing it with -n produces a highest-to-lowest ranking. -u keeps only one line per unique sort key, dropping any further duplicates, which is a fast way to list the distinct values in a column once it has been isolated with cut.

$ tail -n +2 team.csv | sort -t',' -k4 -nr
Frank Miller,Engineering,45,110000
carol white,engineering,41,95000
Alice Johnson,Engineering,29,85000
Eve Davis,Marketing,38,71000
grace hopper,Sales,31,67000
Bob Smith,Marketing,34,62000
David Lee,Sales,26,54000
$ tail -n +2 team.csv | cut -d',' -f2 | sort -u
Engineering
Marketing
Sales
engineering

• Sort on a specific column with -k and -t, e.g. sort -t',' -k3 orders rows by the third comma-separated field.
• -f, also written --ignore-case, folds case so carol and Carol are treated as equal during comparison.
• -h compares human-readable sizes like 2K, 1M, and 3G in the order a person would expect, instead of alphabetically.
• -c checks whether input is already sorted and reports an error without printing anything if it is not.
• Chain a second key with another -k to break ties, e.g. sort -k2,2 -k4,4n sorts by department first and salary second.