readex.ksh

Solaris环境下Shell编程编程

#!/bin/ksh

# Script name: readex.ksh

###### Step 1 - Copy /etc/hosts
cp /etc/hosts /tmp/hosts2


##### Step 2 - Strip out comment lines
grep -v '^#' /tmp/hosts2 > /tmp/hosts3  


##### Step 3 - fd 3 is an input file /tmp/hosts3
exec 3< /tmp/hosts3


##### Step 4 - fd 4 is output file /tmp/hostsfinal
exec 4> /tmp/hostsfinal


#####  The following 4 statements accomplish STEP 5

read -u3 addr1 name1 alias	# read from fd 3 
read -u3 addr2 name2 alias	# read from fd 3

print -u4 $name1 $addr1		# write to fd 4 (do not write aliases)
print -u4 $name2 $addr2		# write to fd 4 (do not write aliases) 

#####  END OF STEP 5 statements


exec 3<&-			# Step 6 - close fd 3

exec 4<&-			# Step 7 - close fd 4