#!/bin/ksh
##
## SCRIPT: grep_10lines_around
##
##                     in $FEDIR/scripts   where $FEDIR=/apps/nns_com/fea
##
##         (May rename to grep3 someday.)                 
#############################################################################
## PURPOSE: Shows ten lines both above and below lines with a match to
##          the string in $1.   The file being searched is named in $2.
##
#############################################################################
## CALL FORMAT: $FEDIR/scripts/grep_10lines_around  <string> <filename>
##
##              Can test with
##                      ./grep_10lines_around tk $HOME/.profile
##                  or
##                      ./grep_10lines_around tool $HOME/.auxchestrc
#############################################################################
## CALLED BY: manually  (and someday in a utility, like a FileTools GUI menu
##                                                 or in nnsFEAmenu 'C')
##
##    Can use an alias in $HOME/.profile, like
##        alias grep10='/apps/nns_com/fea/scripts/grep_10lines_around'
#############################################################################
## MAINTENANCE HISTORY:
## Written by : Blaise Montandon O06 18Oct99 Based on 'grep_3lines_around' 
## Last Update: Blaise Montandon O06 18Oct99 
#############################################################################

#############################################################################
## Check for two input items.
#############################################################################

if test "$1" = ""
then
	echo "
INPUT ERROR:
Supply a string (and filename) to script $0.
Input: <string> <filename>
Exiting ...
"
	exit
fi

if test "$2" = ""
then
	echo "
INPUT ERROR:
Supply a filename to script $0.
Input: <string> <filename>
Exiting ...
"
	exit
fi

## For testing:
#  set -x

#############################################################################
##  Here is a possibly handy SIMPLE EXAMPLE awk program to
##  write all lines whose first field is different from the previous one.
##
##               $1 != prev { print; prev = $1 }
##
##  This grep-extended script is basically a more complex version of this.
#############################################################################

echo "
*.................................................
* Lines in file $2
* that match the string '$1' ---
* including 10 lines above-and-below matches.
* (All lines are preceded by line numbers and an
*  asterisk before a line-number indicates a match.)
*.................................................
"

awk -v STRING="$1" \
'BEGIN  {

##################################################
## The 10 'prev' vars hold the 10 last lines read.
##################################################
prev1 = ""
prev2 = ""
prev3 = ""
prev4 = ""
prev5 = ""
prev6 = ""
prev7 = ""
prev8 = ""
prev9 = ""
prev10 = ""

##################################################
## 'aftcount' holds the integers 10,9,...,2,1, or 0
## --- representing the number of lines after the
## last matched line that need to be printed.
##################################################
aftcount = 0

##################################################
## 'lastprt' holds the line# of the line last printed.
## 'lastprt' is reset any time 'printf' is called.
##################################################
lastprt = 0

}  # end of BEGIN

####################################################
## IF WE HAVE A MATCH, SUSPEND PRINTING
## THREE 'AFTER-A-MATCH-LINES':
## If there is a new match, reset 'aftcount' to zero.
##            (We do not want to print a line twice.)
## We will restart aftcount at 3 after the new match
## line is printed.
####################################################

    $0 ~ STRING  \
       { aftcount = 0 }

######################################################
## PRINT ONE OF THE 3 'AFTER-A-MATCH-LINES':
## If 'aftcount' is non-zero, print the current line.
## We had a match up to 3 lines ago. Decrement 'aftcount'
## and save the number of the printed line in 'lastprt'.
######################################################

    ( aftcount != 0 )  \
       { aftcount = aftcount - 1 ;
         printf (" %s %s \n", NR, $0);
         lastprt = NR }


######################################################
## IF WE HAVE A MATCH, PRINT 3-PREV & CURRENT:
## If there is a match, print the 3 previous lines
## --- as long as their linenums are greater than
## the last-printed line number.  (We do not want
## to print a line twice.)
##
## Then print the current line.  Also set 'aftcount'
## to three, and save the
## number of the matched-printed line in 'lastprt'.
######################################################

   { recnum = NR - 10 }
   ( $0 ~ STRING && recnum > lastprt ) \
                          { printf (" %s %s \n", recnum, prev10); }

   { recnum = NR - 9 }
   ( $0 ~ STRING && recnum > lastprt ) \
                          { printf (" %s %s \n", recnum, prev9); }

   { recnum = NR - 8 }
   ( $0 ~ STRING && recnum > lastprt ) \
                          { printf (" %s %s \n", recnum, prev8); }

   { recnum = NR - 7 }
   ( $0 ~ STRING && recnum > lastprt ) \
                          { printf (" %s %s \n", recnum, prev7); }

   { recnum = NR - 6 }
   ( $0 ~ STRING && recnum > lastprt ) \
                          { printf (" %s %s \n", recnum, prev6); }

   { recnum = NR - 5 }
   ( $0 ~ STRING && recnum > lastprt ) \
                          { printf (" %s %s \n", recnum, prev5); }

   { recnum = NR - 4 }
   ( $0 ~ STRING && recnum > lastprt ) \
                          { printf (" %s %s \n", recnum, prev4); }

   { recnum = NR - 3 }
   ( $0 ~ STRING && recnum > lastprt ) \
                          { printf (" %s %s \n", recnum, prev3); }

   { recnum = NR - 2 }
   ( $0 ~ STRING && recnum > lastprt ) \
                          { printf (" %s %s \n", recnum, prev2); }

   { recnum = NR - 1 }
   ( $0 ~ STRING && recnum > lastprt ) \
                          { printf (" %s %s \n", recnum, prev1); }

    $0 ~ STRING  \
       { printf ("*%s %s \n", NR, $0);
         aftcount = 10;
         lastprt = NR }


######################################################
## Update prev10, prev9, ..., prev3, prev2, and prev1,
## before reading the next line.
######################################################

     { prev10 = prev9; prev9 = prev8; prev8 = prev7; }
      { prev7 = prev6; prev6 = prev5; prev5 = prev4; prev4 = prev3; }
      { prev3 = prev2; prev2 = prev1; prev1 = $0; }

' $2

# }' $2 > $HOME/temp.lis