readex.sh

来自「Solaris环境下Shell编程编程」· Shell 代码 · 共 35 行

#!/bin/sh

# Script name: readex.sh

##### 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 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 <& 3 addr1 name1 alias	# Read from fd 3
read <& 3 addr2 name2 alias	# Read from fd 3

echo $name1 $addr1 >& 4		# Write to fd 4 (do not write aliases)
echo $name2 $addr2 >& 4		# 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