Shell Programming and Scripting

nawk '	# Start nawk script.
# The following section of code is processed when we are reading the 1st input
# file (i.e., when the current number of lines read (NR) is the same as the
# current number of lines read from the current input file (FNR)).
NR == FNR {
	f19[NR] = $1 	# Gather the values that are to be inserted as the new
			# field #19 in subsequent files.
	next		# Read the next input line without processing the
			# remaining steps in this script.
}

# The following section of code is processed when we see the 1st line in any
# subsequent file...
FNR == 1 {
	# Increment a count of the number of files seen...
	if(fc++)
		# and, if it is not the first one, close the previous output
		# file.
		close(ofn)
	# Calculate the the number of characters in the current input line that
	# appear before the spot where the new field is to be added.  It is
	# assumed that the length of the first field in each line is a constant
	# within any input file (which is true by definition when input files
	# contain only one line).
	len = length($1) + 17 * 7
	# Set the output file name to be used when processing this input file.
	ofn = "output" fc
}
# The following section is processed for each line in the current file.
{	# Print the 1st len characters of the current input line, followed by
	# the value to be inserted as field #19 (as a 7 character floating
	# point value with three digits after the decimal point) in this file,
	# followed by the remainder of the current input line to the current
	# output file.
	printf("%s%7.3f%s\n", substr($0, 1, len), f19[fc],
		substr($0, len + 1)) > ofn
}' 7lines input[1-7]
# The above line terminates the nawk script and names the file containing the
# values to be inserted (which much be first) and the names of the input files
# to be modified in the order you want them to be processed.