SORT

Sort a file in ascending order

$ sort names.txt

Sort a file in descending order

$ sort -r names.txt

Sort passwd file by 3rd field.

$ sort -t: -k 3n /etc/passwd | more

Sort a colon delimited text file on 2nd field (employee_id)

$ sort -t: -k 2 names.txt
Emma Thomas:100:Marketing
Alex Jason:200:Sales
Madison Randy:300:Product Development
Sanjay Gupta:400:Support
Nisha Singh:500:Sales

Sort a tab delimited text file on 3rd field (department_name) and suppress duplicates

$ sort -t: -u -k 3 names.txt
Emma Thomas:100:Marketing
Madison Randy:300:Product Development
Alex Jason:200:Sales
Sanjay Gupta:400:Support

Sort the passwd file by the 3rd field (numeric userid)

$ sort -t: -k 3n /etc/passwd | more
root:x:0:0:root:/root:/bin/bash
bin:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/sbin:/sbin/nologin
adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin