Bash - convert time interval string to nr. of seconds

Question

I'm trying to convert strings, describing a time interval, to the corresponding number of seconds.

After some experimenting I figured out that I can use date like this:

soon=$(date -d '5 minutes 10 seconds' +%s); now=$(date +%s)
echo $(( $soon-$now ))

but I think there should be an easier way to convert strings like "5 minutes 10 seconds" to the corresponding number of seconds, in this example 310. Is there a way to do this in one command?

Note: although portability would be useful, it isn't my top priority.

Answer 1

You could start at epoch

date -d"1970-01-01 00:00:00 UTC 5 minutes 10 seconds" "+%s"
310

You could also easily sub in times

Time="1 day"
date -d"1970-01-01 00:00:00 UTC $Time" "+%s"
86400

Answer 2

There is one way to do it, without using date command in pure bash (for portability)

Assuming you just have an input string to convert "5 minutes 10 seconds" in a bash variable with a : de-limiter as below.

$ convertString="00:05:10"
$ IFS=: read -r hour minute second <<< "$convertString"
$ secondsValue=$(((hour * 60 + minute) * 60 + second))
$ printf "%s\n" "$secondsValue"
310

You can run the above commands directly on the command-line without the $ mark.

Answer 3

This will do (add the epoch 19700101):

$ date -ud '19700101 5 minutes 10 seconds' +%s
310

It is important to add a -u to avoid local time (and DST) effects.

$ TZ=America/Los_Angeles date -d '19700101 5 minutes 10 seconds' +%s
29110

---

Note that date could do some math:

$ date -ud '19700101 +5 minutes 10 seconds -47 seconds -1 min' +%s
203

Answer 4

The previous suggestions didn't work properly on alpine linux, so here's a small helper function that is POSIX compliant, is easy to use and also supports calculations (just as a side effect of the implementation).

The function always returns an integer based on the provided parameters.

$ durationToSeconds '<value>' '<fallback>'

$ durationToSeconds "1h 30m"
5400

$ durationToSeconds "$someemptyvar" 1h
3600

$ durationToSeconds "$someemptyvar" "1h 30m"
5400

# Calculations also work
$ durationToSeconds "1h * 3"
10800

$ durationToSeconds "1h - 1h"
0

# And also supports long forms for year, day, hour, minute, second
$ durationToSeconds "3 days 1 hour"
262800

# It's also case insensitive
$ durationToSeconds "3 Days"
259200

function durationToSeconds () {
  set -f
  normalize () { echo $1 | tr '[:upper:]' '[:lower:]' | tr -d "\"\\\'" | sed 's/years\{0,1\}/y/g; s/months\{0,1\}/m/g; s/days\{0,1\}/d/g; s/hours\{0,1\}/h/g; s/minutes\{0,1\}/m/g; s/min/m/g; s/seconds\{0,1\}/s/g; s/sec/s/g;  s/ //g;'; }
  local value=$(normalize "$1")
  local fallback=$(normalize "$2")

  echo $value | grep -v '^[-+*/0-9ydhms]\{0,30\}$' > /dev/null 2>&1
  if [ $? -eq 0 ]
  then
    >&2 echo Invalid duration pattern \"$value\"
  else
    if [ "$value" = "" ]; then
      [ "$fallback" != "" ] && durationToSeconds "$fallback"
    else
      sedtmpl () { echo "s/\([0-9]\+\)$1/(0\1 * $2)/g;"; }
      local template="$(sedtmpl '\( \|$\)' 1) $(sedtmpl y '365 * 86400') $(sedtmpl d 86400) $(sedtmpl h 3600) $(sedtmpl m 60) $(sedtmpl s 1) s/) *(/) + (/g;"
      echo $value | sed "$template" | bc
    fi
  fi
  set +f
}

Answer 5

Edit : Yes. I developed for OP after comment and checked on Mac OS X, CentOS and Ubuntu. One liner, POSIX compliant command for converting "X minutes Y seconds" format to seconds. That was the question .

echo $(($(echo "5 minutes 10 seconds" | cut -c1-2)*60  + $(echo "5 minutes 10 seconds" | cut -c1-12 | awk '{print substr($0,11)}')))

OP told me via comment that he wants for "X minutes Y seconds" format not for HH:MM:SS format. The command with date and "+%s" is throwing error on (my) Mac. OP wanted to grab the numerical values from "X minutes Y seconds" format and convert it to seconds. First I extracted the minute in digit (take it as equation A) :

echo "5 minutes 10 seconds" | cut -c1-2)

then I extracted the seconds part (take it as equation B) :

echo "5 minutes 10 seconds" | cut -c1-12 | awk '{print substr($0,11)}'

Now multiply minute by 60 then add with the other :

echo $((equation A)*60) + (equation B))

OP should ask the others to check my developmental version (but working) of command before using it for automatic repeated usage like we do with cron on a production server.

If we want to run this on a log file with values in "X minutes Y seconds" format, we have to change echo "5 minutes 10 seconds" to cat file | ... cat file | ... like command. I kept a gist of it too if I or others ever need we can use it with cat to run on server log files with x minutes y seconds like log format.

Although off-topic (what I understood, question has not much to do with current time), this is not working for POSIX-compliant OS to get current time in seconds :

date -d "1970-01-01 00:00:00 UTC 5 minutes 10 seconds" "+%s"

It will throw error on MacOS X but work on most GNU/Linux distro. That +%s part will throw error on POSIX-compliant OS upon complicated usage. These commands are mostly suitable to get current time in seconds on POSIX compliant to any kind of unix like OS :

awk 'BEGIN{srand(); print srand()}'
perl -le 'print time' 

If OP needs can extend it by generating current time in seconds and subtract. I hope it will help.

---- OLD Answer before EDIT ----

You can get the current time without that date -- echo | awk '{print systime();}' echo | awk '{print systime();}' or wget -qO- http://www.timeapi.org/utc/now?\\\\s . Other way to convert time to second is echo "00:20:40.25" | awk -F: '{ print ($1 * 3600) + ($2 * 60) + $3 }' echo "00:20:40.25" | awk -F: '{ print ($1 * 3600) + ($2 * 60) + $3 }' .

The example with printf shown in another answer is near perfect.

That thing you want is always needed by the basic utilities of GNU/Linux - gnu.org/../../../../../Setting-an-Alarm.html

Way to approach really depends how much foolproof way you need.