Linux file timestamps - birth, atime, mtime, ctime

file-timestamps.log

birth - created  - touch
birth    2022-12-20 22:56:54.558640670 +0100
access   2022-12-20 22:56:54.558640670 +0100
modify   2022-12-20 22:56:54.558640670 +0100
change   2022-12-20 22:56:54.558640670 +0100

atime - accessed - cat
birth    2022-12-20 22:56:54.558640670 +0100
access   2022-12-20 22:56:55.570654581 +0100
modify   2022-12-20 22:56:54.558640670 +0100
change   2022-12-20 22:56:54.558640670 +0100

mtime - modified - added line
birth    2022-12-20 22:56:54.558640670 +0100
access   2022-12-20 22:56:55.570654581 +0100
modify   2022-12-20 22:56:56.578668421 +0100
change   2022-12-20 22:56:56.578668421 +0100

ctime - changed  - chmod
birth    2022-12-20 22:56:54.558640670 +0100
access   2022-12-20 22:56:55.570654581 +0100
modify   2022-12-20 22:56:56.578668421 +0100
change   2022-12-20 22:56:57.586682257 +0100

times using ls
birth   -rw-r--r-- 1 1000 1000 12 22:56:54.558640670 somefile
atime   -rw-r--r-- 1 1000 1000 12 22:56:55.570654581 somefile
mtime   -rw-r--r-- 1 1000 1000 12 22:56:56.578668421 somefile
ctime   -rw-r--r-- 1 1000 1000 12 22:56:57.586682257 somefile

file-timestamps.sh

#!/bin/bash

# aim of the script is to show the different file timestamps and which action updates which one

stats() {
  stat --printf "birth    %w\naccess   %x\nmodify   %y\nchange   %z\n" somefile
  sleep 1
}

rm -f somefile

# creation of the file
echo -e "\nbirth - created  - touch"
touch somefile
stats

# access the content of the file
echo -e "\natime - accessed - cat"
cat somefile > /dev/null
stats

# modify the content of the file
echo -e "\nmtime - modified - added line"
echo "new content" >> somefile
stats

# change metadata of the file
echo -e "\nctime - changed  - chmod"
chmod +w somefile
stats

echo -e "\ndisplay filetimes using ls"
printf "birth   "
ls --time-style "+%H:%M:%S.%N" -ln --time=birth somefile 
printf "atime   "
ls --time-style "+%H:%M:%S.%N" -ln --time=atime somefile 
printf "mtime   "
ls --time-style "+%H:%M:%S.%N" -ln somefile 
printf "ctime   "
ls --time-style "+%H:%M:%S.%N" -ln --time=ctime somefile