Shell Programming and Scripting

$cat file1.txt
123
234
23e
234.456
234.876e
345.00

 nawk -F'|' 'int($1)!=$1 {printf "Error in field 1|"$0"\n"}' file1.txt

% cat infile 
123
234
23e
234.456
234.876e
345.00
% perl '-MScalar::Util qw(looks_like_number)' -F, -lne'
    print "$_ doesn\47t look like number!" unless looks_like_number $_
    ' infile
23e doesn't look like number!
234.876e doesn't look like number!

awk '$1 !~ /^[0-9]+\.?[0-9]+$/ {print "Error in field 1|" $0}' file1.txt

awk '!($0+0==$0){print $0 " not a number"}' file

awk '$1 !~ /^[0-9]+\.?[0-9]+$/ {print "Error in field 1|" $0}' file1.txt

awk -F\| '{
  for (i = 0; ++i <= NF;)
    if (!isnum($i))
	  printf "line %d, field %i does\47t look like a number: %s\n", \
	    NR, i, $i
  }
func isnum(x) {
  return x == x + 0
  }' infile

% cat infile 
123|123
234|234
23e|23e
234.456|234.456
234.876e|234.876e
345.00|345.00
% awk -F\| '{
  for (i = 0; ++i <= NF;)
    if (!isnum($i))
  printf "line %d, field %i does\47t look like a number: %s\n", \
    NR, i, $i
  }
func isnum(x) {
  return x == x + 0
  }' infile
line 3, field 1 does't look like a number: 23e
line 3, field 2 does't look like a number: 23e
line 5, field 1 does't look like a number: 234.876e
line 5, field 2 does't look like a number: 234.876e

awk -F\| '{
  for (i = 0; ++i <= NF;)
    if (!isnum($i)) {
	  print "line", NR, "contains invalid numbers, skipping it ..."
	  break
	  }
  }
func isnum(x) {
  return x == x + 0
  }' infile

line 3 contains invalid numbers, skipping it ...
line 5 contains invalid numbers, skipping it ...