Shell Programming and Scripting

cd yourDir
grep -El ".*\s.*\s.*\s.*" *.txt

-E, --extended-regexp
              Interpret PATTERN as an extended regular expression (ERE, see below).  (-E is specified by POSIX.)

 -l, --files-with-matches
              Suppress  normal  output; instead print the name of each input file from which output would normally have been printed.
              The scanning will stop on the first match.  (-l is specified by POSIX.)
 ".*\s.*\s.*\s.*" is regular expression to find out the pattern with 4 fields. in your case.

files=$(find . -type f -name '*.txt' | awk -F"/" '{print $NF}')

for i in $files
do
awk 'NF>3{print "Files with more than 3 columns-->",FILENAME}' $i | uniq
done

files=$(find . -type f -name '*.txt' | awk -F"/" '{print $NF}')

for i in $files
do
awk 'NF>3{print "File with at least one line with " NR " columns-->",FILENAME;exit 1}' $i 
done