What you're looking for is date --date='06/12/2012 07:21:22' +"%s". Keep in mind that this assumes you're using GNU coreutils, as both --date and the %s format string are GNU extensions. POSIX doesn't specify either of those, so there is no portable way of making such conversion even on POSIX compliant systems.

Consult the appropriate manual page for other versions of date.

Note: bash --date and -d option expects the date in US or ISO8601 format, i.e. mm/dd/yyyy or yyyy-mm-dd, not in UK, EU, or any other format.

For Linux, run this command:

date -d '06/12/2012 07:21:22' +"%s" 

For macOS, run this command:

date -jf "%Y-%m-%d %H:%M:%S" "1970-01-01 00:00:00" +%s 

A lot of these answers are overly complicated and also are missing how to use variables. This is how you would do it more simply on standard Linux system (as previously mentioned the date command would have to be adjusted for Mac Users) :

Sample script:

#!/bin/bash orig="Apr 28 07:50:01" epoch=$(date -d "${orig}" +"%s") epoch_to_date=$(date -d @$epoch +%Y%m%d_%H%M%S) echo "RESULTS:" echo "original = $orig" echo "epoch conv = $epoch" echo "epoch to human readable time stamp = $epoch_to_date" 

Results in :

RESULTS: original = Apr 28 07:50:01 epoch conv = 1524916201 epoch to human readable time stamp = 20180428_075001 

Or as a function :

# -- Converts from human to epoch or epoch to human, specifically "Apr 28 07:50:01" human. # typeset now=$(date +"%s") # typeset now_human_date=$(convert_cron_time "human" "$now") function convert_cron_time() { case "${1,,}" in epoch) # human to epoch (eg. "Apr 28 07:50:01" to 1524916201) echo $(date -d "${2}" +"%s") ;; human) # epoch to human (eg. 1524916201 to "Apr 28 07:50:01") echo $(date -d "@${2}" +"%b %d %H:%M:%S") ;; esac } 

Just be sure what timezone you want to use.

datetime="06/12/2012 07:21:22" 

Most popular use takes machine timezone.

date -d "$datetime" +"%s" #depends on local timezone, my output = "1339456882" 

But in case you intentionally want to pass UTC datetime and you want proper timezone you need to add -u flag. Otherwise you convert it from your local timezone.

date -u -d "$datetime" +"%s" #general output = "1339485682" 

Efficient way to convert date time string to epoch in bash

Avoiding useless repetitives forks, in order to make this translation a lot quicker...

Instead of running 1 fork for each translation, we could run date -f - +%s as background process...

Intro

Common syntax:

epochDate=$(date -d "$InputDate" +%s) 

Work fine, but become heavy if run repetetively!

In this post, you will find

• a Quick Demo, following this,
• some Explanations,
• a Function useable for many Un*x tools (bc, rot13, sed...).

Quick Demo using coproc

coproc DATE { exec stdbuf -o0 /bin/date -f - +%s 2>&1 ;} echo >&${DATE[1]} 06/12/2012 07:21:22 read -ru${DATE[0]} epochDate printf 'EPOCH: %u Date:%(%c)T\n' $epochDate $epochDate 

EPOCH: 1339478482 Date:Tue Jun 12 07:21:22 2012 

About performances, you could compare:

time for i in {1..900};do echo >&${DATE[1]} "now";read -ru${DATE[0]} ans;done real 0m0.029s user 0m0.018s sys 0m0.005s 

and:

time for i in {1..900};do ans=$(date +%s -d "now");done real 0m1.465s user 0m0.962s sys 0m0.442s 

From more than 1.4 seconds to less than 30 milliseconds!!(on my host).

You could check echo $ans, replace "now" by "2019-25-12 20:10:00" and so on...

Little function

myDate() { if [[ $1 == -v ]]; then local -n out=$2 shift 2 else local out fi echo "$*" >&${DATE[1]} read -ru ${DATE[0]} out [[ ${out@A} == out=* ]] && echo $out case $out in ''|*[!0-9]*) return 1;; esac } 

myDate 06/12/2012 07:21:22 

1339478482 

myDate -v var 06/12/2012 07:21:22 printf '%(%c)T\n' $var 

Tue Jun 12 07:21:22 2012 

myDate -v var wrong string printf 'ResultCode: %d: Var: "%s"\n' "$?" "$var" 

ResultCode: 1: Var: "/bin/date: invalid date 'wrong string'" 

Stop background

You could, once requirement of date subprocess ended:

kill ${DATE_PID} exec {DATE[1]}>&- ; exec {DATE[0]}<&- 

[1]+ Terminated coproc DATE { exec stdbuf -o0 /bin/date -f - +%s; } 

Original post (detailed explanation)

Instead of running 1 fork by date to convert, run date just 1 time and do all convertion with same process (this could become a lot quicker)!:

date -f - +%s <<eof Apr 17 2014 May 21 2012 Mar 8 00:07 Feb 11 00:09 eof 1397685600 1337551200 1520464020 1518304140 

Sample:

start1=$(LANG=C ps ho lstart 1) start2=$(LANG=C ps ho lstart $$) dirchg=$(LANG=C date -r .) read -p "A date: " userdate { read start1 ; read start2 ; read dirchg ; read userdate ;} < <( date -f - +%s <<<"$start1"$'\n'"$start2"$'\n'"$dirchg"$'\n'"$userdate" ) 

Then now have a look:

declare -p start1 start2 dirchg userdate 

(may answer something like:

declare -- start1="1518549549" declare -- start2="1520183716" declare -- dirchg="1520601919" declare -- userdate="1397685600" 

This was done in only one date subprocess execution!

Using long running subprocess

We just need one fifo:

mkfifo /tmp/myDateFifo exec 7> >(exec stdbuf -o0 /bin/date -f - +%s >/tmp/myDateFifo) exec 8</tmp/myDateFifo rm /tmp/myDateFifo 

(Note: As process is running and all descriptors are opened, we could safely remove fifo's filesystem entry.)

Then now:

LANG=C ps ho lstart 1 $$ >&7 read -u 8 start1 read -u 8 start2 LANG=C date -r . >&7 read -u 8 dirchg read -p "Some date: " userdate echo >&7 $userdate read -u 8 userdate 

We could buid a little function:

mydate() { local var=$1; shift; echo >&7 $@ read -u 8 $var } mydate start1 $(LANG=C ps ho lstart 1) echo $start1 

Or use my newConnector function

With functions for connecting MySQL/MariaDB, PostgreSQL and SQLite...

You may find them in different version on GitHub, or on my site: download or show.

wget https://raw.githubusercontent.com/F-Hauri/Connector-bash/master/shell_connector.bash 

wget http://f-hauri.ch/vrac/shell_connector.sh . shell_connector.bash newConnector /bin/date '-f - +%s' @0 0 myDate "2018-1-1 12:00" test echo $test 1514804400 

Nota: On GitHub, functions and test are separated files. On my site test are run simply if this script is not sourced. On GitHub, there is no upgrade anymore! Last verified version is on my site!

# Exit here if script is sourced [ "$0" = "$BASH_SOURCE" ] || { true;return 0;} 

get_curr_date () { # get unix time DATE=$(date +%s) echo "DATE_CURR : "$DATE } conv_utime_hread () { # convert unix time to human readable format DATE_HREAD=$(date -d @$DATE +%Y%m%d_%H%M%S) echo "DATE_HREAD : "$DATE_HREAD } 

I added the following alias to .bashrc (or .zshrc) - note the --utc switch which converts the input as UTC time zone. You can remove it to use the local machine time zone but in my experience I usually want UTC for this:

alias datetoepoch='date --utc +%s -d' 

Now I can just type in the terminal something like:

datetoepoch 2024-03-18 

and get the result:

1710720000

Not exactly asked for, but I use this to convert an OpenLDAP timestamp like 20241111073923Z to seconds since the epoch:

echo $(date -u --date=$(echo "$1" | sed \ -e 's/^\(....\)\(..\)\(..\)\(..\)\(..\)\(..\)Z$/\1-\2-\3T\4:\5:\6/') '+%s') 

For the example timestamp the command executed will be date -u --date=2024-11-11T07:39:23 +%s, and the output will be 1731310763.

A bash function is always faster than exec date, here is the code I used to convert datetime to epoch seconds for computing seconds difference between datetimes. However the timezone is ignored, so it's not exactly epoch seconds. While it could be easy to add timezone offset seconds.

 if [ "${datetime/ /}" != "$datetime" ]; then date="${datetime% *}" time="${datetime##* }" else date="${datetime%-*}" time="${datetime##*-}" fi if [ "${date/-/}" != "$date" ]; then year="${date%%-*}" s="${date#*-}" month=$(( 1"${s%%-*}" - 100 )) day=$(( 1"${s#*-}" - 100 )) else year=${date:0:4} month=$(( 1"${date:4:2}" - 100 )) day=$(( 1"${date:6:2}" - 100 )) fi if [ "${time/:/}" != "$time" ]; then hour=${time%%:*} s=${time#*:} minute=$(( 1"${s%%:*}" - 100 )) second=$(( 1"${s#*:}" - 100 )) else hour=$(( 1"${time:0:2}" - 100 )) minute=$(( 1"${time:2:2}" - 100 )) second=$(( 1"${time:4:2}" - 100 )) fi month0=$(( month - 1 )) day0=$(( day - 1 )) if [ $((year % 100)) == 0 ]; then leap=$(( year % 400 == 0 )) else leap=$(( year % 4 == 0 )) fi if [ $leap == 1 ]; then mo=(31 29 31 30 31 30 31 31 30 31 30 31) mobase=(0 31 60 91 121 152 182 213 244 274 305 335) else mo=(31 28 31 30 31 30 31 31 30 31 30 31) mobase=(0 31 59 90 120 151 181 212 243 273 304 334) fi days_1970=$(( 1970 * 365 + 1970 / 4 - 1970 / 100 + 1970 / 400 )) days_0=$(( year * 365 + year / 4 - year / 100 + year / 400 )) epochday=$(( days_0 - days_1970 + mobase[month0] + day0 )) epochsec=$(( epochday * 86400 + (hour * 60 + minute) * 60 + second ))