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Commands tagged validation from sorted by
Terminal - Commands tagged validation - 5 results
if date -d 2006-10-10 >> /dev/null 2>&1; then echo 1; else echo 0; fi
2013-01-10 10:35:15
Functions: date echo
0

On CentOS at least, date returns a boolean for the common date string formats, including YYYY-MM-DD. In the sample output, you can see various invalid dates returning 0 whereas a simple regex check would return 1 for the invalid dates.

-d, --date=STRING display time described by STRING, not `now'

The version of date on OS X does not appear to have this same option.

curl -s "http://feeds.delicious.com/v2/json?count=5" | python -m json.tool | less -R
2010-03-24 09:15:12
User: keimlink
Functions: less python
11

Validates and pretty-prints the content fetched from the URL.

perl -we 'my $regex = eval {qr/.*/}; die "$@" if $@;'
2009-10-13 21:50:47
User: tlacuache
Functions: eval perl
4

Place the regular expression you want to validate between the forward slashes in the eval block.

if [ "$testnum" -eq "$testnum" 2>/dev/null ]; then echo It is numeric; fi
2009-10-09 14:57:27
User: jgc
Functions: echo
0

Using the standard numeric comparison but suppressing the STDERR output acts as the simplest way to check a value is numeric. See sample output for some examples.

echo 2006-10-10 | grep -c '^[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]$'
2009-05-11 22:18:43
User: rez0r
Functions: echo grep
-1

Quick and easy way of validating a date format of yyyy-mm-dd and returning a boolean, the regex can easily be upgraded to handle "in betweens" for mm dd or to validate other types of strings, ex. ip address.

Boolean output could easily be piped into a condition for a more complete one-liner.