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:

# label (target for branch): :top / < [hH] [123]>.* / { ;# match whole heading ;# save copy of pattern space ;# delete text after closing tag ;# delete text before opening tag h s/\( \). *$/\1/ s/".*\( \)/\1/ ;# print what remains ;# retrieve saved pattern space ;# delete opening tag ;# delete closing tag s/ < [hH] [123]>// s/ // 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