gawk 'BEGIN{
RS="*/"
replace="<span style=\"color:#aaaaaa; font-weight:bold;\">"
}
/\/\* +TODO/{
gsub(/\/\* +TODO/,replace" /* TODO")
RT=RT "</span>"
}
{ print $0RT}
' file
вывод
$ ./shell.sh
int void main ( int h, char * argv[] )
int a, b; <span style="color:#aaaaaa; font-weight:bold;"> /* TODO :
- include libraries
...
*/</span>
foobar();
<span style="color:#aaaaaa; font-weight:bold;"> /* TODO : fix missing {'s */</span>