Compare File's Date Bash

compare file's date bash

You can compare file modification times with test, using -nt (newer than) and -ot (older than) operators:

if [ "$file1" -ot "$file2" ]; then
    cp -f "$file2" "$file1"
fi

Bash compare file last modification date with another date

You need to convert both dates to a common format that is amenable to comparison. You may be able to simply use GNU date to convert both to Unix epoch timestamps:

d1=$(date +%s --date "$file_last_modified_date")  # 1478037600
d2=$(date +%s --date "$variable")                 # 1478099452

Now you can compare them as integers.

if [ "$d1" -gt "$d2" ]; then

Bash Script - Comparing last modified dates

I have rewritten the script without using the date command of the shell, which is not portable across MacOS and GNU Linux. I use ls instead, hoping this command is actually portable. Please check:

#!/bin/bash

## variables commented out since we don't have access to theirs values: 
#remote_file="www.someurl.com/file"
#remote_last_modified_date="$(curl -sI ${remote_file} | grep -E "Last-Modified:" | awk '{print $3,$4,$5,$6}' )"

## let's suppose we get next result into our variables:
local_file="test"
remote_last_modified_date="16 Apr 2020 08:14:26"

## we don't use the date command, not portable across MacOS and GNU Linux
## we use ls command with the option --time-style instead

## rewrite dates to allow comparison in format +"%Y-%m-%d_%H:%M:%S"
local_sortable_date=$(ls -l --time-style=+"%Y-%m-%d_%H:%M:%S" "$local_file"| cut -d ' ' -f 6)

remote_year=${remote_last_modified_date:7:4}
remote_month_name=${remote_last_modified_date:3:3}
remote_month=$(echo $remote_month_name | 
  sed 's/Jan/01/;s/Feb/02/;s/Mar/03/;s/Apr/04/;s/May/05/;s/Jun/06/;
    s/Aug/08/;s/Sep/09/;s/Oct/10/;s/Nov/11/;s/Dec/12/')
remote_day=${remote_last_modified_date:0:2}
remote_time=${remote_last_modified_date:12:8}

remote_sortable_date=${remote_year}-${remote_month}-${remote_day}_$remote_time

if [[ $remote_sortable_date > $local_sortable_date ]] ; then
  echo "A new version is available"
  set of commands
else
  echo "latest update already installed"
fi

Best way to compare Timestamps in Linux shell/bash script?

Why don't you stick with epoch-time? You can get the current time as seconds since epoch by
date +%s, so you just have to compare

if (( (healthcheck_time + 50*60) < $(date +%s) ))
then
  # .... healthcheck older than 50 minutes
fi

Bash - How to compare two files last modified date, when they are remote?

Try this:

remote=$(ssh user@server "stat -c %Y /path/to/remote_file")
[[ -z "$remote" ]] && exit 1 # stop on error ($remote is empty)
local=$(stat -c %Y /path/to/local_file)

if [[ $remote -gt $local ]]; then
  echo remote file is newer
else
  echo local file is newer
fi

Comparing two dates in Linux bash shell script

Just a couple simple syntax modifications:

#!/bin/bash

#Setting variable
now=$(date +"%m-%d-%Y")
#Testing variable
echo "Current System Date: $now"
#Setting variable
filedate=$(date -r hello.sh "+%m-%d-%Y")
#Testing variable
echo "hello.sh date: $filedate"

if [[ $now ==  $filedate ]]
then
    echo "This statement works"
else
    echo "This statement didnt work"
fi

• in the if, you must put spaces after [ and before ]
• you are comparing text, so -ge does not work. the "-" comparisons work for numbers. Here you want to use == to compare text.
• Reflex for me, I put " around echo text.

This will work for cases where the dates are the same. If you need "greater than" or "smaller than", put the dates in timestamp format (+%s) and compare the numbers. Then you could use the -ge or others of the same type.

Date comparison in Bash

You can compare lexicographically with the conditional construct [[ ]] in this way:

[[ "2014-12-01T21:34:03+02:00" < "2014-12-01T21:35:03+02:00" ]]

From the man:

[[ expression ]]

Return a status of 0 or 1 depending on the evaluation of the conditional expression expression.

---

New update:

If you need to compare times with different time-zone, you can first convert those times in this way:

get_date() {
    date --utc --date="$1" +"%Y-%m-%d %H:%M:%S"
}

$ get_date "2014-12-01T14:00:00+00:00"
2014-12-01 14:00:00

$ get_date "2014-12-01T12:00:00-05:00"
2014-12-01 17:00:00

$ [[ $(get_date "2014-12-01T14:00:00+00:00") < $(get_date "2014-12-01T12:00:00-05:00") ]] && echo it works
it works

Bash script compare two date variables

The GNU date command can convert a date into the number of seconds since 1970. Try this script:

#! /bin/bash
DATE=$(date -d "$3-$2-$1 01" '+%s')
COUNT=0
tr '/' ' ' | {
    while read D M Y ; do
    THIS=$(date -d "$Y-$M-$D 01" '+%s')
    if (( THIS > DATE )) ; then
        COUNT=$((COUNT + 1))
    fi
    done
    echo $COUNT
}

It expects three arguments and the raw dates in stdin:

for D in $(seq 19 25) ; do echo $D/08/2007 ; done | ./count.sh 22 08 2007
3

It will work till 2038. ;-)

---

Related Topics