1

I will be receiving data files in a Linux directory.

I need to validate that the file names follow the following pattern "NNN-YYYYMMDD-NNNNNNNNN.pdf" where

  • NNN stands for numeric value (0-9).
  • "YYYYMMDD" stands for valid date. YYYY is the year, MM is the month (between 1-12) and DD is the day of the month (can have values between 01 to 31 depending on the month).
  • NNNNNNNN is a numeric number (i.e. only 0-9 allowed).

What utility (SED, AWK etc.) and how should I use to validate the file name.

11
  • you are looking for some manual started script, which validates a string?
    – Jaleks
    Commented Jul 7, 2017 at 19:44
  • You can do this using grep
    – ryekayo
    Commented Jul 7, 2017 at 19:45
  • Please show me how.
    – AlluSingh
    Commented Jul 7, 2017 at 19:47
  • Can you give me a sample file that you are expecting? Please post it to your question..
    – ryekayo
    Commented Jul 7, 2017 at 19:49
  • Does the year have to be the current year? Or current or prior? Or any from 0000 to 9999?
    – Jeff Schaller
    Commented Jul 7, 2017 at 19:52

4 Answers 4

2

This tests every file in the current directory, using bash's [[ operator, against the pattern:

  • start of string ^
  • 3 digits
  • -
  • 8 digits
  • -
  • 9 digits
  • .pdf
  • end of string $
  • that the middle 8 digits evaluate to a valid date according to GNU date

You can adjust the assumptions above easily enough.

for f in *
do
  [[ $f =~ ^([0-9][0-9][0-9])-([0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9])-([0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]).pdf$ ]] && 
  date -d ${BASH_REMATCH[2]} &>/dev/null && 
  echo Valid: "$f"
done
4
  • nicer one, if year, month and day really always have the correct number count, maybe still remove the accidentally .pdf at the end :-)
    – Jaleks
    Commented Jul 7, 2017 at 20:25
  • Thanks a lot. I changed it to: for f in "123-20170730-123456789.pdf" do [[ $f =~ ^([0-9]{3})-([0-9]{8})-([0-9]{9}).pdf$ ]] && date -d ${BASH_REMATCH[2]} &>/dev/null if [ $? -eq 0 ] then echo "Good File" else echo "Bad File" fi; done
    – AlluSingh
    Commented Jul 7, 2017 at 22:07
  • I have two (2) questions. Question 1: What is "~" in the expression. Question 2: Why does the following statement not work: for f in "123-20170730-123456789.pdf" do echo $f | grep '^([0-9]{3}-([0-9]{8})-([0-9]{9}).pdf$' &> /dev/null if [ $? -eq 0 ] then echo "Good File" else echo "Bad File" fi; done
    – AlluSingh
    Commented Jul 7, 2017 at 22:11
  • @AlluSingh (1): Match a regex … (2) because you need to use *Extended" regex syntax and because you have not closed the first (. This do work: echo "123-20170730-123456789.pdf" | grep -E '^([0-9]{3})-([0-9]{8})-([0-9]{9}).pdf$'
    – user232326
    Commented Jul 7, 2017 at 22:26
1

sounds like:

TOCHECK=( "01-20170228-12345678" "012-20170230-012345678" "01-20170228-12345678" "123-20170730-012345678" )

for CHECK in $(seq 0 $(( ${#TOCHECK[@]}-1 )) ); do
    PARTS=( $(echo ${TOCHECK[$CHECK]} | sed "s/-/ /g")   )   
    echo -ne "\nchecking "
    echo "\"${PARTS[@]}\""
    echo "\"${PARTS[0]}\""
    echo "\"${PARTS[1]}\""
    echo "\"${PARTS[2]}\""

    if echo ${PARTS[0]} | grep "[0-9]\{3\}" ; then
        echo first part ok
    fi

    if echo ${PARTS[2]} | grep "[0-9]\{9\}" ; then
        echo last part ok
    fi  

    date --date="${PARTS[1]}"
    RES=$?
    echo $RES
    if [ 0$RES -eq 0 ]; then
        echo date OK
    fi  
done

(just some conceptual idea, of course to be modified)

1

It's not enough to use regexps. The validation is 2 steps: regexp matching and date validation. Here's a Python implementation:

from __future__ import print_function
import sys 
import re
import datetime

def validate(filename):
    match = re.match(r"[0-9]{3}-([0-9]{8})-[0-9]{8}\.pdf", filename)
    if not match:
        return False
    datestr = match.group(1)
    try:
        datetime.date(int(datestr[:4]), int(datestr[4:6]), int(datestr[6:8]))
    except ValueError:
        return False
    else:
        return True

if __name__ == "__main__":
    if validate(sys.argv[1]):
        print(":-)")
        sys.exit(0)
    else:
        print(":-(")
        sys.exit(1)

Usage: python validate.py FILE

One can probably use grep and date to do the same.

1

One basic solution, using grep. Doesn't do the detailed date checking aspect, instead merely checks it's numeric.

if ls|grep -vE '^[0-9]{3}-[0-9]{8}-[0-9]{8}\.pdf$'; then
    echo some bogus files found
else
    echo all good
fi
0

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