[SOLVED!] Arrange and set date / time extracted from http header in linux router with single curl or wget line

LinuxMintyFresh · 05-13-2018, 06:13 PM

So the following techniques do extract the date and time, the problem is it is not arranged properly for this particular setup. Months must be changed to numbers.

Method 1:

Code:

dateFromServer=$(curl -v --silent https://google.com/ 2>&1 \
 | grep Date | sed -e 's/< Date: //')
date +"%d%m%Y%H%M%S" -d "$dateFromServer"

The result is

'ate: invalid date 'Sat, 12 May 2018 18:49:18 GMT

I have tried re-arranging the code of this first command and it achieves nothing, ordering always stays the same.

Method 2: Get the date from a HTTP response header. Remove clutter. Set the date.

Code:

date -s `curl -I 'https://startpage.com/' 2>/dev/null | grep -i '^date:' | sed 's/^[Dd]ate: //g'`

The results I get are as follows:

Quote:

@Heyzeus:/tmp/home/root# date -s `curl -I 'https://google.com/' 2>/dev/null | grep -i '^date:' | sed 's/^[Dd]ate: //g'` BusyBox v1.25.1 (2018-05-06 13:19:15 EDT) multi-call binary.

Usage: date [OPTIONS] [+FMT] [TIME]

Display time (using +FMT), or set time

[-s,--set] TIME Set time to TIME
-u,--utc Work in UTC (don't convert to local time)
-R,--rfc-2822 Output RFC-2822 compliant date string
-I[SPEC] Output ISO-8601 compliant date string SPEC='date' (default) for date only, 'hours', 'minutes', or 'seconds' for date and time to the indicated precision
-r,--reference FILE Display last modification time of FILE
-d,--date TIME Display TIME, not 'now'
-D FMT Use FMT for -d TIME conversion

Recognized TIME formats: hh:mm[:ss] [YYYY.]MM.DD-hh:mm[:ss] YYYY-MM-DD hh:mm[:ss] [[[[[YY]YY]MM]DD]hh]mm[.ss] 'date TIME' form accepts MMDDhhmm[[YY]YY][.ss] instead
Another

Method 3:

Code:

 date -s "$(wget -qSO- --max-redirect=0 startpage.com 2>&1 | grep Date: | cut -d' ' -f5-8)"

results in: date: invalid date '13 May 2018 22:46:44' [wget code results in the closest match]

The time extracted in the first results is for example: "Sat, 12 May 2018 18:49:18 GMT" and date -s on AsusWRT requires something more like 2018-05-12 18:49:18 [this works] Or as listed under "recognized time formats."

For the first one, "Sat," needs to be removed, month needs replacing with a number, and then arranged properly; Wget requires the month be turned to a number, and arranged as follows 2018-05-12 18:49:18; Would like to have curl and certainly wget versions if possible.

If this could be done exclusively in a single terminal command that would be phenomenal.

LinuxMintyFresh · 05-13-2018, 07:28 PM

Code:

date -u -D '%a, %d %b %Y %H:%M:%S' -d "$(curl -I 'https://1.1.1.1/' 2>/dev/null | grep -i '^date:' | sed 's/^[Dd]ate: //g')"

results in the following:

successfully sets inaccurate date & time (off by a day): Mon May 14 00:22:52 UTC 2018
time is actually Sun May 13 00:17:31

syg00 · 05-13-2018, 07:32 PM

Very likely a limitation in the busybox date implementation - in which case you'd have to do your own parsing. sed (amongst others) would work using capture groups.

Edit: you posted while I was (slowly) typing. Above was in reference to your initial post.

LinuxMintyFresh · 05-14-2018, 04:24 PM

Thanks to Twiglets https://www.snbforums.com/threads/nt...-3#post-404882

Here is an alternative that DOES set the date !!! [-s option].
Prints out 'Date' it retrieves & the 'Date' that is set for comparison.

This works on the AsusWRT / Merlin, the only thing that is odd is that the date retrieved is ".... GMT" and the date utility sets the correct time but changes it to "... DST"
Environment has TZ set to "GMT"

Code:

datetext=$(curl -I 'https://1.1.1.1/' 2>/dev/null | grep "Date:" |sed 's/Date: [A-Z][a-z][a-z], //g'| sed 's/\r//') ; echo "Date Retrieved = $datetext" ; echo -n "Date set = " ; date -s "$datetext" -D'%d %b %Y %T %Z'