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bash date validate

bash date validate

bash date validate

I am writing a simple script in bash so that it is easily portable, is there an easy way to validate a string is a date?


My string should come back in the format "2013-03-07" CCYY-MM-DD however it may be blank or anything, if it's not in a date format then I would like to ignore it.

CODE -->

if [ $mydatestring == validdate ] ; then
    ...do some stuff... 

RE: bash date validate

Found a quick way round this.

CODE -->

if (date --date $mydatestring > /dev/null 2>&1); then 

RE: bash date validate


Just to check the format in Bash 3.0 or newer I would prefer :

CODE --> Bash

[[ "$date" =~ ^[[:digit:]]{4}(-[[:digit:]]{2}){2}$ ]] 

But personally I would allow dates in any format understood by GNU date. ( Systems with Bash usually have such date implementation. ) The following will transform many valid date formats to CCYY-MM-DD and reduces the unknown formats and invalid dates to empty string :


date="$( date -d '2013-03-07' +'%F' 2> /dev/null )"
[[ "$date" ]] || echo 'error : missing, invalid or incorrectly formatted date' 


RE: bash date validate

Thanks feherke good to know the format option as well, handy for pattern matching things other than dates too.

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