date

Common formats

date +"%H:%M:%S"
date +"%T"

Matches ProjectDiscovery tools’ timestamp format:

date +"%Y-%m-%dT%H:%M:%S.%N%:z"

Easy-to-read log format:

date +'[%d-%b-%Y %T]'
# [30-Sep-2025 16:20:08]

Filename-safe UTC timestamp

date -u +"%Y-%m-%dT%H%M%SZ"
# 2026-09-09T213740Z

Sorts correctly as a string, has no characters that need escaping in a filename (no :), and is unambiguous across timezones since it’s always UTC.

$(now) alias

Uses the same filename-safe UTC format, so it plugs straight into a filename:

alias now='date -u +"%Y-%m-%dT%H%M%SZ"'

touch "$(now)-filename-part2.ext"
# 2026-09-09T213740Z-filename-part2.ext

As reusable functions

getDateTime () {
        date +'[%d-%b-%Y %T]'
}
 
getTimestamp () {
        date +"%Y-%m-%dT%H:%M:%S.%N%:z"
}