Date command

Shell Programming and Scripting
1

Hello Forum,

I want to retrieve the old date from "date" command.
For example: It's 02 Nov today and i want 7 days old date say 25 oct
then how can i do that???
As i do
date | awk '{print $3-7}'
It returns -5 (As 2-7)
So can anyone help me to solve this out..... I think by making function, it would be easier but i want to do this by making One liner command as i mentioned.....
Any kind of help and suggession would be appreciated.....

Many Thanks
Lokesh

2

If you have GNU date, then

date --date "7 days ago"

I think the Perderabo's datecalc can also handles these requests.

3

Hi,

I couldnot think of a one-liner command as u said.
Please find below a script, which calculates previous date..i.e current date-1

Can you please check, if modifying this script a bit will work in your case

Script below
---------------
day=`date +%d%`
month=`date +%m%`
year=`date +%Y`
daynm=`date +%a`

    case "$daynm" in
            "Mon"\) day=\`expr "$day" - 3\`
            k=3;;
            "Sun"\) day=\`expr "$day" - 2\`
            k=2;;
            *\) day=\`expr "$day" - 1\`
            k=1;;
    esac
    if test $day -le 0
    then
    month=\`expr "$month" - 1\`
            case "$month" in
                    0\)
                    month=12
                    year=\`expr "$year" - 1\`
                    ;;
            esac
            m=\`expr $day - 1\`
    day=\`cal $month $year | grep . | fmt -1 | tail $m | head -1\`
    fi

    if [[ "$\{day\}" = [0-9] ]]
    then
            day="0"$day
    fi

    if [[ "$\{month\}" = [0-9] ]]
    then
        month="0"$month
    fi
    Final_Date=$year$month$day

echo $Final_Date

Thanks ,
Suresh Sampat

4

You can print the date if you're looking for "hours earlier/later than right now" by manipulating the TZ variable:

# date
Mon Nov  5 09:47:32 CST 2007

# TZ=$(((6+24*7))) date  
Mon Oct 29 09:47:37  2007

It's a bit cheap :slight_smile: but it works. Note that I needed to start with 6 for my local timezone, and then add hours to go backward (7 days of 24 hours each).