How to count days for DebianReleases
The Script
#!/bin/bash # cound_days.sh # %s seconds since 1970-01-01 00:00:00 UTC echo Bullseye=20210814 Bookworm=20230610 echo "Bullseye=$Bullseye" echo "Bookworm=$Bookworm" echo S1=$(date --date="$Bullseye" +%s) S2=$(date --date="$Bookworm" +%s) S3=$(( 24 * 60 * 60 )) echo "Seconds from 19700101: $S1" echo "Seconds from 19700101: $S2" echo "Seconds in 24 hours : $S3" echo TS=$(( $S2 - $S1 )) echo "$S2 - $S1 = $TS" echo "Time in Seconds: $TS" echo TD=$(( $TS / $S3 )) echo "$TS / $S3 = $TD" echo "Time in Days: $TD" echo
The Result
$ ./count_days.sh Bullseye=20210814 Bookworm=20230610 Seconds from 19700101: 1628924400 Seconds from 19700101: 1686380400 Seconds in 24 hours : 86400 1686380400 - 1628924400 = 57456000 Time in Seconds: 57456000 57456000 / 86400 = 665 Time in Days: 665