how do I check in bash whether a file was created more than x time ago?

user_63051 0
Viewed 121206

I want to check in linux bash whether a file was created more than x time ago.

let's say the file is called text.txt and the time is 2 hours.

 if [ what? ]
 then
     echo "old enough"
 fi
linux command-line bash
8 Answers

Only for modification time

if test `find "text.txt" -mmin +120`
then
    echo old enough
fi

You can use -cmin for change or -amin for access time. As others pointed I don’t think you can track creation time.

user_509020

I always liked using date -r /the/file +%s to find its age.

You can also do touch --date '2015-10-10 9:55' /tmp/file to get extremely fine-grained time on an arbitrary date/time.

user_946110

Creation time isn't stored.

What are stored are three timestamps (generally, they can be turned off on certain filesystems or by certain filesystem options):

  • Last access time
  • Last modification time
  • Last change time

a "Change" to the file is counted as permission changes, rename etc. While the modification is contents only.

Phil_10870

Consider the outcome of the tool 'stat':

  File: `infolog.txt'
  Size: 694         Blocks: 8          IO Block: 4096   regular file
Device: 801h/2049d  Inode: 11635578    Links: 1
Access: (0644/-rw-r--r--)  Uid: ( 1000/     fdr)   Gid: ( 1000/     fdr)
Access: 2009-01-01 22:04:15.000000000 -0800
Modify: 2009-01-01 22:05:05.000000000 -0800
Change: 2009-01-01 22:05:05.000000000 -0800

You can see here the three dates for Access/modify/change. There is no created date. You can only really be sure when the file contents were modified (the "modify" field) or its inode changed (the "change" field).

Examples of when both fields get updated:

"Modify" will be updated if someone concatenated extra information to the end of the file.

"Change" will be updated if someone changed permissions via chmod.

user_668710

I use

file_age() {
    local filename=$1
    echo $(( $(date +%s) - $(date -r $filename +%s) ))
}

is_stale() {
    local filename=$1
    local max_minutes=20
    [ $(file_age $filename) -gt $(( $max_minutes*60 )) ]
}

if is_stale /my/file; then
    ...
fi
user_1648020
Related