GNU sort on Linux is not giving expected results on my csv file. Can you please help to resolve the situation/ issue?
Input file
[nscruser]$ cat cemp1.txt
10,30
50,900
20,1050
Objective I need to do numeric sort on the first field for the above file
[nscruser]$ sort -t',' -k1 -n cemp1.txt
10,30
50,900
20,1050
Expected output But I expected the output as below as I am doing a numeric sort on first column
10,30
20,1050
50,900
Can someone please let me know why the discrepancy?
Looking at the man page of sort (from GNU coreutils 8.32),
-k, --key=KEYDEF sort via a key; KEYDEF gives location and type
...
KEYDEF is F[.C][OPTS][,F[.C][OPTS]] for start and stop position, where F is a field number and C a character position in the field; both are origin 1, and the stop position defaults to the line's end. If neither -t nor -b is in effect, characters in a field are counted from the beginning of the preceding whitespace. OPTS is one or more single-letter ordering options [bdfgiMhnRrV], which over‐ ride global ordering options for that key. If no key is given, use the entire line as the key. Use --debug to diagnose incorrect key usage.
First, you can use --debug as suggested,
$ sort -t',' -k1 -n --debug cemp1.txt
sort: text ordering performed using ‘en_IE.UTF-8’ sorting rules
sort: key 1 is numeric and spans multiple fields
10,30
_____
_____
50,900
______
______
20,1050
_______
_______
That gives us a clue: "key 1 is numeric and spans multiple fields".
As the man page says, "the stop position defaults to the line's end". So you need to add a stop position:
$ sort -t',' -k1,1 -n cemp1.txt
10,30
20,1050
50,900
sort. The native sort on BSD systems does not seem to have this quirk.
$ sort --version output is sort (GNU coreutils) 8.28 ...; @user1626902, which version are you running? or maybe the sorting rules of en_IE.UTF-8 is causing the problem. What happens if you prefix the command line with LANG=C
C or POSIX locale. Using LC_ALL=C sort ... would be the other solution to the user's issue.
You could try to prefix your command with LANG or LC_ALL locale variables :
LANG=C sort -t',' -k1,1 -n cemp1.txt
or
LC_ALL=C sort -t',' -k1,1 -n cemp1.txt
The variable used depends on the command and/or the OS version. On HP-UX 11.31 (Unix SYSTEM 5) : man 3C locale extract
LANG LC_MESSAGES
LC_ALL LC_MONETARY
LC_COLLATE LC_NUMERIC
LC_CTYPE LC_TIME
sort?