Using sort -M to sort by month

Question

I have a file months.txt with the following text:

JAN, MAR, DEC, FEB, JUN, APR

In bash I write the following line of code:

cat months.txt | sort -M

I assumed that this would output the text file, sorted by month. However the output is not sorted. Am I using sort incorrectly?

`sort` sorts by line. All your months are on the same line. – Barmar Jun 19 '14 at 00:20 — Barmar, Jun 19 '14 at 00:20

score 2 · Accepted Answer · answered Jun 19 '14 at 00:20

sort sorts lines of text, and you've only given it one.

If your file looked like this:

JAN
MAR
DEC
FEB
JUN
APR

... you'd get the result you expect.

Incidentally, your command is a useless use of cat: the command

sort -M months.txt

does exactly the same thing.

score 1 · Answer 2 · answered Jun 19 '14 at 00:23

1

You need to turn the comma-separated list into separate lines, sort it, and then convert it back:

tr ',' '\n' < months.txt | sort -M | awk 'NR > 1 { printf(",") } {printf("%s", $0)} END { print "" }'

answered Jun 19 '14 at 00:23

Barmar

score 1 · Answer 3 · answered Jun 19 '14 at 00:37

1

Another take:

tr -s ', ' '\n\n' < months.txt | sort -M | paste -sd,

JAN,FEB,MAR,APR,JUN,DEC

No whitespace in the output.

answered Jun 19 '14 at 00:37

glenn jackman

3 Answers3