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mac

Mac vs Linux Date

Converting Mac and Linux Dates

Linux

#!/bin/bash
start_time=$(date +%s)
log=$(date -d @$start_time +%Y%m%d-%H%M%S) 
start=$(date -d @$start_time)
echo $start_time
echo $log
echo $start
sleep 10
stop_time=$(date +%s)
stop=$(date -d @$stop_time)
echo $stop_time
echo $stop

Mac

#!/bin/bash
start_time=$(date +%s)
log=$(date -r $start_time +%Y%m%d-%H%M%S) 
start=$(date -r $start_time)
echo $start_time
echo $log
echo $start
sleep 10
stop_time=$(date +%s)
stop=$(date -r $stop_time)
echo $stop_time
echo $stop

Same output for both

1692292771
20230817-171931
Thu Aug 17 05:19:31 PM UTC 2023
1692292781
Thu Aug 17 05:19:41 PM UTC 2023

Gsed

The sed utility on a Mac OS running Z shell or zsh is a little different compared to gnu’s sed.

Install gnu sed on Mac OS.

brew install gnu-sed

Use gsed instead of sed.

gsed --version

Date From A Year Ago

Here’s a handy little script that has multiple applications to calculate date from a year ago.

#!/bin/bash
now=$(date +%Y%m%d-%H%M%S)
# mac os
year_old=$(date -v-1y +%Y%m%d-%H%M%S) 
# linux os 
year_old=$(date -d "-1 year" +%Y%m%d-%H%M%S)
echo $now
echo $year_old

Mac Os and Linux has slightly different formats. Pick one based on your OS.

Results

20230618-084940
20220618-084940