Shell Programming and Scripting

sort -t- -k3 list.txt

yz-789-abc123
yz-456-abc456
yz-123-abc789
vwx-789-def123
vwx-456-def456
vwx-123-def789
stu-789-ghi123
stu-456-ghi456
stu-123-ghi789
pqr-789-jkl123
pqr-456-jkl456
pqr-123-jkl789
mno-789-mno123
mno-456-mno456
mno-123-mno789
jkl-789-pqr123
jkl-456-pqr456
jkl-123-pqr789
ghi-789-stu123
ghi-456-stu456
ghi-123-stu789
def-789-vwx123
def-456-vwx456
def-123-vwx789
abc-789-yz123
abc-456-yz456
abc-123-yz789

sort -t- -k3n list.txt

abc-123-yz789
abc-456-yz456
abc-789-yz123
def-123-vwx789
def-456-vwx456
def-789-vwx123
ghi-123-stu789
ghi-456-stu456
ghi-789-stu123
jkl-123-pqr789
jkl-456-pqr456
jkl-789-pqr123
mno-123-mno789
mno-456-mno456
mno-789-mno123
pqr-123-jkl789
pqr-456-jkl456
pqr-789-jkl123
stu-123-ghi789
stu-456-ghi456
stu-789-ghi123
vwx-123-def789
vwx-456-def456
vwx-789-def123
yz-123-abc789
yz-456-abc456
yz-789-abc123

$
$
$
$ # Third field does not start with a number, hence the effect of -k3n is unknown (output is unsorted apparently)
$
$ cat list.txt
abc-123-yz789
abc-456-yz456
abc-789-yz123
def-123-vwx789
def-456-vwx456
def-789-vwx123
ghi-123-stu789
ghi-456-stu456
ghi-789-stu123
yz-789-abc123
$
$
$ sort -t- -k3n list.txt
abc-123-yz789
abc-456-yz456
abc-789-yz123
def-123-vwx789
def-456-vwx456
def-789-vwx123
ghi-123-stu789
ghi-456-stu456
ghi-789-stu123
yz-789-abc123
$
$
$
$ # Third field starts with a number, hence -k3n sorts on the maximum number sequence it could extract from the beginning of 3rd field
$
$ cat list1.txt
abc-123-789yz
abc-456-456yz
abc-789-123yz
def-123-789vwx
def-456-456vwx
def-789-123vwx
ghi-123-789stu
ghi-456-456stu
ghi-789-12stu
yz-789-123abc
$
$
$ sort -t- -k3n list1.txt
ghi-789-12stu
abc-789-123yz
def-789-123vwx
yz-789-123abc
abc-456-456yz
def-456-456vwx
ghi-456-456stu
abc-123-789yz
def-123-789vwx
ghi-123-789stu
$
$