Convert a given time to seconds in solaris

Here is a shell function that doesn't require perl:

function d2ts{    typeset d=$(echo "$@" | tr -d ':- ' | sed 's/..$/.&/')    typeset t=$(mktemp) || return -1    typeset s=$(touch -t $d $t 2>&1) || { rm $t ; return -1 ; }    [ -n "$s" ] && { rm $t ; return -1 ; }    truss -f -v 'lstat,lstat64' ls -d $t 2>&1 | nawk '/mt =/ {printf "%d\n",$10}'    rm $t}

$ d2ts 2013-04-29 08:17:58           1367216278

Note that the returned value depends on your timezone.

$ TZ=GMT d2ts 2013-04-29 08:17:581367223478

How it works:

• The first line converts the parameters to a format suitable for touch (here "2013-04-29
• 08:17:58" -> "201304290817.58" )
• The second line creates a temporary file
• The third line change the modification time of the just created file to the required value
• The fourth line aborts the function if setting the time failed, i.e. if the provided time is invalid
• The fifth line traces the ls command to get the file modification time and prints it as an integer
• The sixth line removes the temporary file

In C/C++ on UNIX, you can convert directly:

struct tm tm;time_t t;tm.tm_isdst = -1;if (strptime("2013-04-29 08:17:58", "%Y-%m-%d %H:%M:%S", &tm) != NULL) {    t = mktime(tm);}cout << "seconds since epoch: " << t;

See Opengroup manpage strptime() for the example.

I admire the strace/touch niftyness and the creativity behind it. Though, well, just don't do this in a tight loop ...