[SWLUG] grep question

[bascule]

following some advice from telsa at the weekend i have answered my own 
question by knocking up a script to do what i want...
...except that that's a lie, it took me ages! :-)
i've pasted the scrpt below, there are some obvious flaws, there is no way to 
pass arguments to the internal grep command (without altering the actual 
script) and no means to show a screenfull at a time, i'd welcome comments, 
esp. if i've missed some obvious and easier way of doing something, 

On Friday 08 February 2002 10:22 pm, you wrote:
> if i am feeding a file to grep that has an expression on each line to
> search through another file for matches, is there a way to output the line
> of the file that has the matching expression as well as the match, or to
> specify which line of the file to use as an expression?

--------begin--------
#!/bin/bash
# bgrep (bascule's grep)
# this script feeds a file with patterns to grep and returns (if exists) both 
a
 match from
# a second file and the pattern that matches it
# Usage: bgrep [-p] PATTERN_FILE FILE
# Search for matching expressions from file PATTERN_FILE that occur in file 
FILE
#
# Options:
#  -p: pause between each set of matches that is found
#
if [ $# -eq 2 ] && [ -f $1 ] && [ -f $2 ]
	then
	PATTERN_FILE=$1
	FILE=$2
	args=0
elif [ $# -eq 3 ] && [ $1 = -p ] && [ -f $2 ] && [ -f $3 ]
	then
	PATTERN_FILE=$2
	FILE=$3
	args=0
else
	args=1
fi

case $args in

	0)
lines=`wc -l $PATTERN_FILE|gawk '{print $1}'`
let flag=1
while [ "$flag" -le "$lines" ]
	do
	echo "The pattern: `echo $(head -$flag $PATTERN_FILE|tail -1)`"
	echo "         matches..."
	grep "`echo $(head -$flag $PATTERN_FILE|tail -1)`" $FILE
		if [ $? = 1 ]
		then
		echo "    no matches found "
		elif [ $1 = -p ]
		then
		echo "Press <Enter> to continue"
		read input
		fi
	let flag="$flag + 1"
done
;;

	1)
echo "Usage: bgrep [-p] PATTERN_FILE FILE"
echo "Search for matching expressions from file PATTERN_FILE that occur in 
file
 FILE"
echo ""
echo "Options:"
echo "  -p: pause between each set of matches that is found"
echo ""
exit
;;
esac
---------end--------------

bascule

-- 
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