Command "who -b" behaves differently

Question

I am trying to parse system boot time from "who -b" output.

#define _XOPEN_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <ctype.h>

void GetSystemTurnOnTime()
{
 FILE *fp;
 char *pTemp = NULL;
 char szBuffer[1024] = {0};
 int iLen;
 struct tm tm;
 char buf[255];

 fp = popen("who -b", "r");
 fgets(szBuffer, sizeof(szBuffer), fp);

 pTemp = szBuffer;
 while(isspace(*pTemp))
    ++pTemp;
 iLen = strlen(pTemp);
 pTemp[iLen - 1] = '\0';
 printf("%s\n", pTemp);

 pclose(fp);
}


int
main(void)
{
 GetSystemTurnOnTime();
 exit(EXIT_SUCCESS);
}

Output: In normal execution it gives : system boot 2015-07-31 11:08

If i integrate with daemon then it gives: Jul 31 11:08

if i execute daemon with gdb then it again gives: system boot 2015-07-31 11:08 can any one help me why it is giving two different format.

I belive the output format depends on some of the `LC_*` environment variables. — Filipe Gonçalves, Jul 31 '15 at 12:05
See http://unix.stackexchange.com/questions/98793/who-b-date-format-varies-strangely — Barmar, Jul 31 '15 at 12:06

score 1 · Accepted Answer · edited Aug 03 '15 at 13:26

1

you can use following command:

who -b | awk '{$1=""; $2=""; print $0}' | date -f -

edited Aug 03 '15 at 13:26

dbush

205,898
23
218
273

answered Aug 03 '15 at 13:14

Ravi Bhushan

253
3
17

Command "who -b" behaves differently

1 Answers1