gman

#!/bin/bash
# G-Man: A simple tool for quick & easy access to MAN pages in GNOME
#
# This tool is a graphical frontend which uses Zenity and basic command
# line tools to locate a MAN page in the local filesystem and display it
# with Yelp (the GNOME Help Center).
#
# Author: Dimitris Lampridis <dlampridis_at_gmail.com>

# (C) Copyright 2009 Dimitris Lampridis
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.


# To begin with, set the app title and version
TITLE="G-Man"
VERSION="0.60"

# Set window title and window width
WINDOW_TITLE=$TITLE" (v"$VERSION")"
WINDOW_WIDTH=400
WINDOW_HEIGHT=250

# Paths to needed executables. Please adjust as necessary
ZENITY=/usr/bin/zenity
AWK=/usr/bin/awk
SED=/bin/sed
WHATIS=/usr/bin/whatis
MAN=/usr/bin/man

# Check if Zenity can be found. If not, produce error message
# (with "xmessage", since zenity is not available) and bail out
if [ ! -e "$ZENITY" ]; then
    xmessage "ERROR: $ZENITY not found. You must install the Zenity\
 package, or provide an alternative location"
    exit
fi

# Check if Whatis can be found. If not, produce error message and bail out
if [ ! -e "$WHATIS" ]; then
    $ZENITY --warning --text="ERROR: $WHATIS not found. You must install the \
    man-db package, or provide an alternative location" --title="$WINDOW_TITLE"
    exit
else
    # Look whether $WHATIS is actually a script (man vs man-db) and flag it so
    file $WHATIS | grep -qi "shell script"
    if [ $? -eq 0 ]; then ISBINARY=0; else ISBINARY=1; fi;
fi

# Check if Awk can be found. If not, produce error message and bail out
if [ ! -e "$AWK" ]; then
    $ZENITY --warning --text="ERROR: $AWK not found. You must install the \
Awk package, or provide an alternative location" --title="$WINDOW_TITLE"
    exit
fi

# Check if Sed can be found. If not, produce error message and bail out
if [ ! -e "$SED" ]; then
    $ZENITY --warning --text="ERROR: $SED not found. You must install the \
Sed package, or provide an alternative location" --title="$WINDOW_TITLE"
    exit
fi

# Check if BROWSER is defined, else revert to default X sys browser
if [ -z $BROWSER ]; then
	if [ -e "/usr/bin/x-www-browser" ]; then
		XBROWSER=/usr/bin/x-www-browser
	fi
fi

# Loop until a candidate page is found, or user cancels
CLI=0
PAGEFOUND=0
while [ $PAGEFOUND -eq 0 ]; do

    # Check if user has provided a name as a command-line argument. If not,
    # create a text entry dialog. In any case, save user input as $ENTRY.
    if [ $# -gt 0 ] && [ $CLI -eq 0 ]; then
        ENTRY=$1
        CLI=1
    else
        ENTRY=$($ZENITY --width $WINDOW_WIDTH --entry --title="$WINDOW_TITLE" \
            --text="Please enter a MAN page:")
           
    fi

    # If user aborts, zenity returns nothing, and $ENTRY will be zero length,
    # so bail out
    if [ -z "$ENTRY" ] ; then
        exit
    fi

    # Check if there is any page at all
    PAGECHECK=$($WHATIS $ENTRY | grep -v "nothing appropriate")
    if [ -z "$PAGECHECK" ]; then
        # Check whether we are running whatis from man or man-db.
        # (Man cannot perform a substring search)
        if [ $ISBINARY -eq 1 ]; then
            # Ask user whether to do a substring search
            $ZENITY --question --title="$WINDOW_TITLE" \
                --text="No exact hit found. Would you like a substring search?"
            if [ $? -eq 0 ]; then
                # Redefine $WHATIS to treat $ENTRY as a regular
                # expression and try again
                WHATIS="$WHATIS -r"
                REGEXPCHECK=$($WHATIS $ENTRY | grep -v "nothing appropriate")
                # Nothing found...
                if [ -z "$REGEXPCHECK" ]; then
                    $ZENITY --warning --text="Page \"$ENTRY\" not found" \
                        --title="$WINDOW_TITLE"
                else
                    PAGEFOUND=1
                fi
            fi
        else
            $ZENITY --warning --text="Page \"$ENTRY\" not found" \
                --title="$WINDOW_TITLE"
        fi
    else
        PAGEFOUND=1
    fi
done

# Count number of results (output lines of "whatis")
LINECOUNT=$($WHATIS $ENTRY | wc -l)

# If more than one line are returned, create a list window with zenity and
# save selection in $SELECTION
if [ $LINECOUNT -gt 1 ]; then
    LISTMESSAGE="Multiple pages found. Please select one:"
    SELECTION=$($WHATIS $ENTRY | \
        awk  'BEGIN {FS="[ \t]+-[ \t]+"} {printf "%s\n%s\n", $1, $2}' | \
        $ZENITY --width $WINDOW_WIDTH --height $WINDOW_HEIGHT \
        --list --text="$LISTMESSAGE" --title="$WINDOW_TITLE" \
        --column=Name/Section --column=Description)

    # If user presses OK in the previous dialog without selecting
    # an item from the list (or just presses Cancel), Zenity returns
    # an empty string. Bail out (again)
    if [ -z "$SELECTION" ]; then
        exit
    fi

# If only one result exists, then $SELECTION defaults to that
# result and no list window appears
else
    SELECTION=$($WHATIS $ENTRY)
fi

# Finally, use awk to get all the relevant fields of the selected result
# First, we get the page name (first field of $SELECTION)
NAME=$(echo $SELECTION | $AWK '{print $1}')

# Then we get the section name (second field of $SELECTION)
SECTION=$(echo $SELECTION | $AWK '{print $2}' | $SED 's/[()]//g')

# Finally, call man and exit script
if [ -z $XBROWSER ]; then
	$MAN -H $SECTION $NAME
else
	$MAN --html=$XBROWSER $SECTION $NAME
fi