Shell Programming and Scripting

<td>
<td style=color:green align=center>
</td>
</tr>
</table>

<td style=color:green align=center>
</td>
</tr>
</table>

awk '{if($0 ~ /<td style/){Q=$0;} else {if(Q){print Q}};Q=$0}'   Input_file

awk '{if($0 ~ /<td style/){Q=$0;} else {if(NR>1){print Q}};Q=$0}'  Input_file

<td style=color:green align=center>
</td>
</tr>

sed '/<td>/ {N;s/^<td>\n\(<td style=\)/\1/}' file

sed '/<td>/ {$!N;s/^<td>\n\(<td style=\)/\1/;}' file

 If we found <td> first check to see if this is not the last line "$!", append
 the next line "N" into the pattern space which now contains two lines separated
 by newline "\n".  The \(through\) identifies a pattern (here the word "through")
 to be played back with \1.  The "s" command finds <td> on one line and
 <td style= on the next and replaces it with just <td style=, deleting the first line
 and keeping the next one intact.

#!/usr/bin/env bash

# @(#) s1       Demonstrate find match, delete previous line, ed.

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

original=${1-original}
FILE=data1
rm -f $FILE
cp $original $FILE
E=expected-output.txt

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

pl " Expected output:"
cat $E

# Find match, current line number is in symbol "."
# The previous line is ".-1", so delete that line.
pl " Results, from ed:"
ed $FILE <<EOF
/<td style=/
.-1d
w
q
EOF

pl " Results, content of edited file:"
tee f1 < $FILE 

pl " Verify results if possible:"
C=$HOME/bin/pass-fail
[ -f $C ] && $C || ( pe; pe " Results cannot be verified." ) >&2

exit 0

$ ./s1

Environment: LC_ALL = C, LANG = C
(Versions displayed with local utility "version")
aix 7.1.0.0
bash GNU bash 4.2.10
ed - ( /usr/bin/ed, Sep 5 2012 )
pass-fail - ( local: RepRev 1.8, ~/bin/pass-fail, Nov 18 17:57 )

-----
 Input data file data1:
<td>
<td style=color:green align=center>
</td>
</tr>
</table>

-----
 Expected output:
<td style=color:green align=center>
</td>
</tr>
</table>

-----
 Results, from ed:
62
<td style=color:green align=center>
57

-----
 Results, content of edited file:
<td style=color:green align=center>
</td>
</tr>
</table>

-----
 Verify results if possible:

-----
 Comparison of        4 created lines with        4 lines of desired results:
 Succeeded -- files (computed) f1 and (standard) expected-output.txt have same content.