#!/usr/bin/env bash

# @(#) s2       Demonstrate extraction of lines before and after match.

if uname -a | grep -i solaris 
then
  echo " ( Note -using ggrep )"
  G=/usr/sfw/bin/ggrep
else
  echo " ( Note -using grep )"
  G=grep
fi

# Utility functions: print-as-echo, print-line-with-visual-space, debug.
# export PATH="/usr/local/bin:/usr/bin:/bin"
pe() { for _i;do printf "%s" "$_i";done; printf "\n"; }
pl() { pe;pe "-----" ;pe "$*"; }
db() { ( printf " db, ";for _i;do printf "%s" "$_i";done;printf "\n" ) >&2 ; }
db() { : ; }
C=$HOME/bin/context && [ -f $C ] && $C nawk $G

FILE=${1-data1}

pl " Input data file $FILE:"
cat $FILE

pl " Expected output:"
cat expected-output.txt

pl " Results:"
nawk '/Starting/ { N=0 } {L[++N]=$0 } END { for(X=1; (X<=N); X++) print L[X] }' $FILE |
$G -E -A2 -B1 -i 'error|warning' 

exit 0

$ ./s2
SunOS vm-solaris 5.10 Generic_137138-09 i86pc i386 i86pc
 ( Note -using ggrep )

Environment: LC_ALL = POSIX, LANG = POSIX
(Versions displayed with local utility "version")
OS, ker|rel, machine: SunOS, 5.10, i86pc
Distribution        : Solaris 10 10/08 s10x_u6wos_07b X86
bash GNU bash 3.00.16
nawk - ( /usr/bin/nawk, Jan 8 2007 )
/usr/sfw/bin/ggrep grep (GNU grep) 2.5

-----
 Input data file data1:
it is Starting 
line1
line2
ERROR
line3
line4

it is Starting
line5
ERROR
line6
line7

it is Starting
line8
WARNING
line8.8
line8.9
line9
ERROR
line10
line11

-----
 Expected output:
line8
WARNING
line8.8

line9
ERROR
line10

-----
 Results:
line8
WARNING
line8.8
line8.9
line9
ERROR
line10
line11