GAWK: Inverse of strftime() - Convert date string to seconds since epoc timestamp using format pattern

Question

Gnu AWK provides the built in function

strftime()

which can convert a timestamp like 1359210984 into Sat 26. Jan 15:36:24 CET 2013. I couldn't find a function that would do this:

seconds = timefromdate("Sat 26. Jan 15:36:24 CET 2013", "%a %d. %b %H:%M:%S CET %Y")

or

seconds = timefromdate("2013-01-26 15:36:24", "%Y-%m-%d %H:%M:%S")

Whereas seconds then is 1359210984.

So, the date string should be convertable by a format pattern.

I'd like to do this in gawk only.

Edit 1:

I'd like to convert the date only in gawk for further processing of the stream.

Edit 2:

I've clarified my question. It was a bit sloppy in the "would do this" code example.

Answer 1

The function you're looking for is called mktime(). You should use the gensub() function to manipulate the datespec into the format that can be read by mktime().

---

To format the second example that you give, consider:

BEGIN {
    t = "2013-01-26 15:36:24"
    f = "\\1 \\2 \\3 \\4 \\5 \\6"

    s = mktime(gensub(/(....)-(..)-(..) (..):(..):(..)/, f, "", t))

    print s
}

Results on my machine:

1359178584

---

To format the first example that you give, consider:

BEGIN {
    t = "Sat 26. Jan 15:36:24 CET 2013"

    gsub(/\.|:/, FS, t)
    split(t,a)

    Y = a[8]
    M = convert(a[3])
    D = a[2]

    h = a[4]
    m = a[5]
    s = a[6]

    x = mktime(sprintf("%d %d %d %d %d %d", Y, M, D, h, m, s))

    print x
}

function convert(month) {

    return(((index("JanFebMarAprMayJunJulAugSepOctNovDec", month) - 1) / 3) + 1)
}

Results on my machine:

1359178584

---

For more information, please consult the manual, specifically time functions and string functions. HTH.