For those scripts needing a single do-it-all tool, a Swiss army knife, there is Perl. Perl combines the capabilities of sed and awk, and throws in a large subset of C, to boot. It is modular and contains support for everything ranging from object-oriented programming up to and including the kitchen sink. Short Perl scripts lend themselves to emb…

shellwrapper.sh

#!/bin/bash
 
# Adds up a specified column (of numbers) in the target file.
# Floating-point (decimal) numbers okay, because awk can handle them.
 
ARGS=2
E_WRONGARGS=85
 
if [ $# -ne "$ARGS" ] # Check for proper number of command-line args.
then
   echo "Usage: `basename $0` filename column-number"
   exit $E_WRONGARGS
fi
 
filename=$1
column_number=$2
 
#  Passing shell variables to the awk part of the script is a bit tricky.
#  One method is to strong-quote the Bash-script variable
#+ within the awk script.
#     $'$BASH_SCRIPT_VAR'
#      ^                ^
#  This is done in the embedded awk script below.
#  See the awk documentation for more details.
 
# A multi-line awk script is here invoked by
#   awk '
#   ...
#   ...
#   ...
#   '
 
 
# Begin awk script.
# -----------------------------
awk '
 
{ total += $'"${column_number}"'
}
END {
     print total
}     
 
' "$filename"
# -----------------------------
# End awk script.
 
 
#   It may not be safe to pass shell variables to an embedded awk script,
#+  so Stephane Chazelas proposes the following alternative:
#   ---------------------------------------
#   awk -v column_number="$column_number" '
#   { total += $column_number
#   }
#   END {
#       print total
#   }' "$filename"
#   ---------------------------------------
 
 
exit 0