numberit

UNIX[1].shell范例精解(第4版)_code

#!/bin/bash
# Program name: numberit
# Put line numbers on all lines of memo
if (( $# <  1 )) 
then
	echo "Usage: $0 filename " >&2
	exit 1
fi

count=1                      # Initialize count

cat $1 | while read line    
# Input is coming from file provided at command line
do
   ((count == 1)) && echo "Processing file $1..." > /dev/tty  
   echo -e "$count\t$line"
   let count+=1
done > tmp$$	 		             # Output is going to a temporary file
mv tmp$$ $1