sed: Can't open /usr/web/plan9/sources.html awk ' /^{/ { if (prev != "") { # comments can be trouble (e.g. ffree()) if ( (c = match(prev, /\/\*.*\*\/$/)) != 0 ) { comment = substr(prev, c) sub(/\/\*.*\*\/$/, "", prev) } else comment = "" x = prev # isolate argument list sub(/^[^(]*\(/, "", x) sub(/\)[^)]*$/, "", x) # find the names in it n = split(x, args) arglist = "" for (i = 2; i <= n; i += 2) arglist = arglist args[i] gsub(/\(\*f\)\(Tchar\)/, "f", arglist) # special case for n4.c gsub(/\[[0-9]+\]/, "", arglist) # for n8.c gsub(/[*()\[\]]/, "", arglist) # discard noise characters *()[] gsub(/,/, ", ", arglist) # space nicely sub(/\(.*\)/, "(" arglist ")", prev) # reconstruct print prev comment # argument declarations gsub(/,/, ";", x) gsub(/\(\*f\)\(Tchar\)/, "(*f)()", x) # special case for n4.c if (x != "") print "\t" x ";" } prev = $0 next } { print prev prev = $0 } END { print prev } ' $* sed: Can't open /usr/web/plan9/sources.html