+Usage: man [-m <mode>] [-b <browser>]
+
+-m: Set output format (text, roff or html). Default: roff.
+-b: Use the specified browser. Implies html mode.
+
+If stdout is not associated with a terminal device, the command
+dumps the man page to stdout and exits.
+
+Otherwise, it tries to display the manual page as follows. In text
+mode, plain text is piped to $PAGER. In roff mode, the roff output
+is filtered through nroff, then piped to $PAGER. For both formats,
+if $PAGER is unset, less(1) is assumed.
+
+In html mode, html output is written to a temporary file, and this
+file is displayed as a page in the web browser. If -b is not given,
+the command stored in the $BROWSER environment variable is executed
+with the path to the temporary file as an argument. If $BROWSER is
+unset, elinks(1) is assumed.
+'
+
+_gsu_read_line()
+{
+ local -n p="$1"
+ local l OIFS="$IFS"
+
+ IFS=
+ read -r l || return
+ IFS="$OIFS"
+ p="$l"
+}
+
+_gsu_change_roffify_state()
+{
+ local -n statep="$1"
+ local new_state="$2"
+ local old_state="$statep"
+
+ [[ "$old_state" == "$new_state" ]] && return 0
+
+ case "$old_state" in
+ text);;
+ example) printf '.EE\n';;
+ enum) printf '.RE\n';;
+ esac
+ case "$new_state" in
+ text);;
+ example) printf '.EX\n';;
+ enum) printf '.RS 2\n';;
+ esac
+
+ statep="$new_state"
+ return 1
+}
+
+_gsu_print_protected_roff_line()
+{
+ local line="$1"
+ local -i n=0
+
+ while [[ "${line:$n:1}" == ' ' ]]; do
+ let n++
+ done
+ line="${line:$n}"
+ printf '\\&%s\n' "${line//\\/\\\\}"
+}
+
+_gsu_roffify_maindoc()
+{
+ local state='text' TAB=' '
+ local line next_line
+ local -i n
+
+ _gsu_read_line 'line' || return
+ while _gsu_read_line next_line; do
+ if [[ "$next_line" =~ ^(----|====|~~~~) ]]; then # heading
+ printf '.SS %s\n' "$line"
+ _gsu_read_line line || return
+ _gsu_change_roffify_state 'state' 'text'
+ continue
+ fi
+ if [[ "${line:0:1}" == "$TAB" ]]; then # example
+ _gsu_change_roffify_state 'state' 'example'
+ printf '%s\n' "$line"
+ line="$next_line"
+ continue
+ fi
+ n=0
+ while [[ "${line:$n:1}" == ' ' ]]; do
+ let n++
+ done
+ line=${line:$n};
+ if [[ "${line:0:1}" == '*' ]]; then # enum
+ line=${line#\*}
+ _gsu_change_roffify_state 'state' 'enum'
+ printf '\n\(bu %s\n' "$line"
+ line="$next_line"
+ continue
+ fi
+ if [[ "$line" =~ ^$ ]]; then # new paragraph
+ _gsu_change_roffify_state 'state' 'text'
+ printf '.PP\n'
+ else
+ _gsu_print_protected_roff_line "$line"
+ fi
+ line="$next_line"
+ done
+ _gsu_print_protected_roff_line "$line"
+}
+
+_gsu_extract_maindoc()
+{
+ sed -e '1,/^#\{70,\}/d' -e '/^#\{70,\}/,$d' -e 's/^# *//' -e 's/^#//g' "$0"
+}
+
+_gsu_roffify_cmds()
+{
+ local line cmd= desc= state='text' TAB=' '
+
+ while _gsu_read_line line; do
+ if [[ "${line:0:1}" != '#' ]]; then # com_foo()
+ line="${line#com_}"
+ cmd="${line%()}"
+ continue
+ fi
+ line="${line####}"
+ if [[ "$line" =~ ^[[:space:]]*$ ]]; then
+ printf '.PP\n'
+ _gsu_change_roffify_state 'state' 'text'
+ continue
+ fi
+ if [[ -n "$cmd" ]]; then # desc or usage
+ if [[ -z "$desc" ]]; then # desc
+ desc="$line"
+ continue
+ fi
+ # usage
+ _gsu_change_roffify_state 'state' 'text'
+ printf '\n.SS %s \\- %s\n' "$cmd" "$desc"
+ printf '\n.I %s\n' "$line"
+ cmd=
+ desc=
+ continue
+ fi
+ line="${line# }"
+ if [[ "${line:0:1}" == "$TAB" ]]; then
+ _gsu_change_roffify_state 'state' 'example'
+ _gsu_print_protected_roff_line "$line"
+ continue
+ fi
+ if [[ "$line" == -*:* ]]; then
+ _gsu_change_roffify_state 'state' 'enum'
+ printf '.PP\n.B %s:\n' "${line%%:*}"
+ _gsu_print_protected_roff_line "${line#*:}"
+ continue
+ fi
+ _gsu_print_protected_roff_line "$line"
+ done
+}
+
+_gsu_roffify_autocmd()
+{
+ local cmd="$1" help_txt="$2"
+
+ {
+ printf 'com_%s()\n' "$cmd"
+ sed -e 's/^/## /g' <<< "$help_txt"
+ } | _gsu_roffify_cmds
+}