Consider again the sed code of Figure 14.1. It is tempting to write the first of the compound statements as follows (note the differences in the three substitution commands):

Explain why this doesn’t work.

Figure 14.1:

Transcribed Image Text:

# label (target for branch): :top /< [hH] [123]>.*<\/ [hH] [123]>/ { ;# match whole heading ;# save copy of pattern space ;# delete text after closing tag ;# delete text before opening tag h s/\(<\/[hH] [123]>\). *$/\1/ s/".*\(<[hH] [123]>\)/\1/ ;# print what remains ;# retrieve saved pattern space ;# delete opening tag ;# delete closing tag s/< [hH] [123]>// s/<\/ [hH] [123] >// b top ;# and branch to top of script ;# match opening tag (only) /< [hH] [123]>/ { N ;# extend search to next line b top ;# and branch to top of script d. ;# if no match at all, delete