Shell Programming and Scripting

titleA
titleB
TEST
titleC
TEST

# Recall N lines ago up to 9 lines
function last(N)
{
        if(N>L) return("");
        return(LINE[(L-N)%10]);
}

{ LINE[(++L)%10]=$0 } # Remember line for later

# If this line and the last line don't match titlex, print last line.
(last(1) ~ /TEST/) && /TEST/        { print last(1) }

# Do the same test for the last line by itself.
END {   if(last(0) ~ /TEST/) print last(0); }

$ cat regafter2.awk

# Recall N lines ago up to 9 lines
function last(N)
{
        if(N>L) return("");
        return(LINE[(L-N)%10]);
}

{ LINE[(++L)%10]=$0 } # Remember line for later

# If this line and the last line don't match titlex, print last line.
(last(1) != REJECT) && $0 != REJECT { print last(1) }
# Do the same test for the last line by itself.
END {   if(last(0) != REJECT) print last(0); }

$ awk -v REJECT="TEST" -f regafter2.awk data2

titleA

$

titleA
titleB
TEST FILLER
titleC
TEST

#!/usr/bin/env bash

# @(#) s2	Demonstrate search for pattern-accept followed by pattern-reject.
# See http://sourceforge.net/projects/cgrep/

# 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 cgrep

FILE=${1-data3}
ACCEPT="title"
REJECT="TEST"

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

pl " Results, $ACCEPT to $REJECT:"
cgrep -a "^.*$ACCEPT.*\n.*$REJECT" $FILE
pl " Results, invert $ACCEPT to $REJECT:"
cgrep -v -a "^.*$ACCEPT.*\n.*$REJECT" $FILE

exit 0

% ./s2

Environment: LC_ALL = C, LANG = C
(Versions displayed with local utility "version")
OS, ker|rel, machine: Linux, 2.6.26-2-amd64, x86_64
Distribution        : Debian GNU/Linux 5.0.8 (lenny) 
bash GNU bash 3.2.39
cgrep ATT cgrep 8.15

-----
 Input data file data3:
titleA
titleB
TEST FILLER
titleC
TEST

-----
 Results, title to TEST:
titleB
TEST FILLER
titleC
TEST

-----
 Results, invert title to TEST:
titleA

$ cat regafter3.awk
# Recall N lines ago up to 9 lines
function last(N)
{
        if(N>L) return("");
        return(LINE[(L-N)%10]);
}

{ LINE[(++L)%10]=$0 } # Remember line for later

# If this line and the last line don't match titlex, print last line.
(last(1) !~ REJECT) && $0 !~ REJECT { print last(1) }
# Do the same test for the last line by itself.
END {   if(last(0) !~ REJECT) print last(0); }

$ awk -v REJECT="TEST.*" -f regafter3.awk data3

titleA

$