A simple program to emit the current UTC time, but also renames files with the file's timestamp

utc

#!/usr/bin/python3

import time
import sys
import os

now_timestamp = time.time()
now = time.localtime(now_timestamp)

# time.struct_time(tm_year=2017, tm_mon=1, tm_mday=10, tm_hour=15, tm_min=45, tm_sec=17, tm_wday=1, tm_yday=10, tm_isdst=0
)

name = os.path.basename(sys.argv[0])

def usage():
    print ("utc - emit current time/date suitable form for scripts")
    print ()
    print ("Usage:")
    print ("    utc               - emit YYYYMMDD")
    print ("    utc --long (utcl) - emit YYYYMMDD.HHMMSS")
    print ("    utc --fine (utcf) - emit YYYYMMDD.HHMMSS.sub_second_part")
    print ("    utc --help, -h    - This help")
    print ()
    print ("Note sub_second relates to the instant the script is launched and is the raw")
    print ("floating point part of the time")
    print ()
    print ("Note: utcl and utcf are aliases")


long = False
fine = False

def make_stamp(now):
    fmt = "%04d%02d%02d"  # Default, short
    data =  ( now.tm_year, now.tm_mon, now.tm_mday )

    if long:
        fmt = "%04d%02d%02d.%02d%02d%02d"
        data = data + ( now.tm_hour, now.tm_min, now.tm_sec )

    if fine:
        sub_second = str(now_timestamp - int(now_timestamp))
        fmt = "%04d%02d%02d.%02d%02d%02d.%s"
        data = data + ( sub_second[2:], )

    stamp = fmt % data
    return stamp


if __name__ == "__main__":
    filenames = [ x for x in sys.argv if not x.startswith("-") ][1:]
    args = [ x for x in sys.argv if x.startswith("-") ]
    
    if args:
        if ("--help" in args) or ("-h" in args):
            usage()
            sys.exit(0)
        if "--long" in args:
            long = True
        if "--fine" in args:
            long = True
            fine = True
    
    if name == "utcl":
        long = True
    if name == "utcf":
        long = True
        fine = True

    stamp = make_stamp(now)

    if filenames:
        for filename in filenames:
           try:
               x = os.stat(filename)
           except OSError as e:
               print (e)
               continue
           stamp = make_stamp(time.localtime(x.st_mtime))
           print ("Rename", filename, "as", stamp+"." +filename)
           os.rename(filename, stamp+"."+filename)
    else:
        print (stamp)

Example usage:

Given:

$ stat foo.py|grep Modify
Modify: 2019-09-27 14:48:18.552274814 +0100

Then:

$ utc
20201029

$ utc --long
20201029.171350

$ utc --fine
20201029.171357.18145465850830078

Also:

$ utc foo.py
# renames foo.py to 20190927.foo.py

$ utc --long foo.py
# renames foo.py to 20190927.144818.foo.py

$ utc --fine foo.py
# renames foo.py to 20190927.144818.7630362510681152.foo.py

$ utc *
# renames all files in a directory based on their timestamp