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Validate date format in a shell script

由 為{幸葍}努か 提交于 2020-01-08 17:42:27

问题


I have to create a Shell Script wherein one of the parameters will be the date in the format dd/mm/yyyy. My question is, how can I check if the Date passed as parameter really follows this Date Format? I tried to use the grep command as below:

if echo "$1" | grep -q '^[0-3][0-9]/[0-1][0-9]/[0-9]\{4\}$'

but it didn't give the correct format because the day for example can be 33, 34, (...), that is not really the correct format. Anyone know something that can really check if the date passed really follows the format dd/mm/yyyy ?


回答1:


Use date

date "+%d/%m/%Y" -d "09/99/2013" > /dev/null  2>&1
 is_valid=$?

If you do not get 0 then date is in invalid format.




回答2:


The simplest solution, that still works perfectly, is the following :

if [[ $1 =~ ^[0-9]{4}-[0-9]{2}-[0-9]{2}$ ]] && date -d "$1" >/dev/null 2>&1
   ...

It consists in combining 2 checks :

  • the first part checks that $1 is of this format : NNNN-NN-NN
  • the second part checks that it is a valid date

You need the two checks because :

  • if you don't do the first check, date will exit with code 0 even if your variable is a valid date in another format
  • if you don't do the second check, then you can end up with a 0 even for variables such as 2016-13-45



回答3:


This function expects 2 strings,a format string, a date string

The format string uses the codes from the date command but does not include the '+'

The function returns 0 if the provided date matches the given format, otherwise it returns 1

datecheck() {
    local format="$1" d="$2"
    [[ "$(date "+$format" -d "$d" 2>/dev/null)" == "$d" ]]
}



回答4:


First, check the form of the input using the regex. Then use awk to switch to mm/dd/yyyy and use date to validate. You can use the following expression in your if statement:

echo "$1" | egrep -q '^[0-3][0-9]/[0-1][0-9]/[0-9]{4}$' && date -d "$(echo "$1" | awk 'BEGIN{FS=OFS="/"}{print $2"/"$1"/"$3}')" >/dev/null 2>&1



回答5:


Simplest way for dd/mm/yyyy exactly in Bash is:

if [[ $1 == [0-3][0-9]/[0-1][0-9]/[0-9][0-9][0-9][0-9] ]]

Or

if [[ $1 =~ ^[0-3][0-9]/[0-1][0-9]/[0-9]{4}$ ]]



回答6:


How about using awk:

echo "31/12/1999" | awk  -F '/' '{ print ($1 <= 31 && $2 <= 12 && match($3, /^[1-9][1-9][1-9][1-9]$/)) ? "good" : "bad" }'

It prints "good" if its valid date else prints "bad"




回答7:


#! /bin/bash

isDateInvalid()
{
    DATE="${1}"

    # Autorized separator char ['space', '/', '.', '_', '-']
    SEPAR="([ \/._-])?"

    # Date format day[01..31], month[01,03,05,07,08,10,12], year[1900..2099]
    DATE_1="((([123][0]|[012][1-9])|3[1])${SEPAR}(0[13578]|1[02])${SEPAR}(19|20)[0-9][0-9])"

    # Date format day[01..30], month[04,06,09,11], year[1900..2099]
    DATE_2="(([123][0]|[012][1-9])${SEPAR}(0[469]|11)${SEPAR}(19|20)[0-9][0-9])"

    # Date format day[01..28], month[02], year[1900..2099]
    DATE_3="(([12][0]|[01][1-9]|2[1-8])${SEPAR}02${SEPAR}(19|20)[0-9][0-9])"

    # Date format day[29], month[02], year[1904..2096]
    DATE_4="(29${SEPAR}02${SEPAR}(19|20(0[48]|[2468][048]|[13579][26])))"

    # Match the date in the Regex

    if ! [[ "${DATE}" =~ "^(${DATE_1}|${DATE_2}|${DATE_3}|${DATE_4})$" ]]
    then
        echo -e "ERROR - '${DATE}' invalid!"
    else
        echo "${DATE} is valid"
    fi
}

echo
echo "Exp 1: "`isDateInvalid '12/13/3000'`
echo "Exp 2: "`isDateInvalid '12/11/2014'`
echo "Exp 3: "`isDateInvalid '12 01 2000'`
echo "Exp 4: "`isDateInvalid '28-02-2014'`
echo "Exp 5: "`isDateInvalid '12_02_2002'` 
echo "Exp 6: "`isDateInvalid '12.10.2099'`
echo "Exp 7: "`isDateInvalid '31/11/2000'`



回答8:


Here's a function to do some data validation this:

# Script expecting a Date parameter in MM-DD-YYYY format as input
verifyInputDate(){
    echo ${date} | grep '^[0-9][0-9]-[0-9][0-9]-[0-9][0-9][0-9][0-9]$'
    if [ $? -eq 0 ]; then
         echo "Date is valid"
     else
          echo "Date is not valid"
     fi
}



回答9:


`X="2016-04-21" then check for the below value being 1 or 0.

cal echo $x | cut -c 6-7 echo $x | cut -c 1-4 2>/dev/null | grep -c echo $x | cut -c 9-10

If the value is 1, then it's valid, else it's not valid.




回答10:


I wrote this bash script to validate date. I can accept mont as alphanumeric.

#!/bin/bash

function isDateValid {
    DATE=$1

    if [[ $DATE =~ ^[0-9]{1,2}-[0-9a-zA-Z]{1,3}-[0-9]{4}$ ]]; then
        echo "Date $DATE is a number!"
        day=`echo $DATE | cut -d'-' -f1`
        month=`echo $DATE | cut -d'-' -f2`
        year=`echo $DATE | cut -d'-' -f3`

                if [ "$month" == "01" ] || [ "$month" == "1" ]; then
                        month="Jan"
                elif [ "$month" == "02" ] || [ "$month" == "2" ]; then
                        month="Feb"
                elif [ "$month" == "03" ] || [ "$month" == "3" ]; then
                        month="Mar"
                elif [ "$month" == "04" ] || [ "$month" == "4" ]; then
                        month="Apr"
                elif [ "$month" == "05" ] || [ "$month" == "5" ]; then
                        month="May"
                elif [ "$month" == "06" ] || [ "$month" == "6" ]; then
                        month="Jun"
                elif [ "$month" == "07" ] || [ "$month" == "7" ]; then
                        month="Jul"
                elif [ "$month" == "08" ] || [ "$month" == "8" ]; then
                        month="Aug"
                elif [ "$month" == "09" ] || [ "$month" == "9" ]; then
                        month="Sep"
                elif [ "$month" == "10" ]; then
                        month="Oct"
                elif [ "$month" == "11" ]; then
                        month="Nov"
                elif [ "$month" == "12" ]; then
                        month="Dec"
                fi

        ymd=$year"-"$month"-"$day
        echo "ymd: "$ymd
        dmy=$(echo "$ymd" | awk -F- '{ OFS=FS; print $3,$2,$1 }')
        echo "dmy: "$dmy
        if date --date "$dmy" >/dev/null 2>&1; then
                echo "OK"
            return 0
        else
                echo "NOK"
            return 1
        fi
    else
        echo "Date $DATE is not a number"
        return 1
    fi
}


if isDateValid "15-15-2014"; then
    echo "date is valid =)"
else
    echo "bad format date"
fi
echo "==================="
if isDateValid "15-12-2014"; then
        echo "date is valid =)"
else
        echo "bad format date"
fi
echo "==================="
if isDateValid "15-Dec-2014"; then
        echo "date is valid =)"
else
        echo "bad format date"
fi
echo "==================="
if isDateValid "1-May-2014"; then
        echo "date is valid =)"
else
        echo "bad format date"
fi
echo "==================="
if isDateValid "1-1-2014"; then
        echo "date is valid =)"
else
        echo "bad format date"
fi
echo "==================="
if isDateValid "12-12-2014"; then
        echo "date is valid =)"
else
        echo "bad format date"
fi



回答11:


Though the solution (if [[ $1 =~ ^[0-9]{4}-[0-9]{2}-[0-9]{2}$ ]] && date -d "$1" >/dev/null 2>&1) of @https://stackoverflow.com/users/2873507/vic-seedoubleyew is best one at least for linux, but it gives error as we can not directly compare/match regex in if statement. We should put the regex in a variable and then we should compare/match that variable in if statement. Moreover second part of if condition does not return a boolean value so this part will also cause error.

So I have done slight modification in the above formula and this modification can also be customized further for various other formats or combination of them.

DATEVALUE=2019-11-12
REGEX='^[0-9]{4}-[0-9]{2}-[0-9]{2}$'
if [[ $DATEVALUE =~ $REGEX ]] ; then
    date -d $DATEVALUE 
  if [ $? -eq 0 ] ; then
    echo "RIGHT DATE"
   else 
    echo "WRONG DATE"
  fi
else
 echo "WRONG FORMAT"
fi



回答12:


Blockquote

DATE = "$*"

[[ "${DATE}" != @(((([123][0]|[012][1-9])|3[1])?([ \/._-])(0[13578]|1[02])?([ \/._-])(19|20)[0-9][0-9])|(([123][0]|[012][1-9])?([ \/._-])\
(0[469]|11)?([ \/._-])(19|20)[0-9][0-9])|(([12][0]|[01][1-9]|2[1-8])?([ \/._-])02?([ \/._-])(19|20)[0-9][0-9])|(29?([ \/._-])02?([ \/._-])\
(19|20(0[48]|[2468][048]|[13579][26])))) ]] && echo error || echo good)


来源：https://stackoverflow.com/questions/18731346/validate-date-format-in-a-shell-script

标签
bash
shell
date
unix
if-statement
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