source: vendor/bash/3.1/examples/scripts.v2/fman

#! /bin/bash
#
# original from:
# fman: new man program
# @(#) fman.ksh 1.5 94/04/16
# 91/07/03 john h. dubois iii ([email protected])
# 91/07/11 made it unpack man pages if neccessary
# 91/07/16 fixed test for whether man file pattern was expanded
# 92/01/21 made it read /etc/default/man to get section order,
#          and only display the first section found.
# 92/02/06 changed name to fman
# 92/02/07 fixed bug in notfound
# 92/02/13 incorporated changes from DOS version
# 92/03/11 changed to use MANPATH from environment if set,
#          and search all directories given in MANPATH
# 92/03/15 exec pager or man w/o forking
# 92/05/31 try using index if one exists
# 92/10/01 Added "See also <other sections>"
# 92/10/18 If PAGER is less, search for name of man page to make it easier
#          to find information in man pages for multiple items
# 92/11/11 Make it work for compressed files not listed in index;
#          deal with man pages listed in index that don't exist.
# 93/03/30 Fixed bug in MANPATH processing
# 93/06/17 Include paths in "See also:" message if they would be needed
#          to get to a man page.  Allow MANPATH spec on command line.
# 93/07/09 Added -h and -e options.
# 94/04/16 Added x option.
#
# conversion to bash v2 syntax done by Chet Ramey

istrue()
{
        test 0 -ne "$1"
}

isfalse()
{
        test 0 -eq "$1"
}

# Finds all sections that man page $1 is in and puts them in the the
# global array Sections[].  
# The filename of each page is put in FileNames[] with the same index.
# Global vars used:
# patharr[] MANPATH directories.

FindSectionsInIndex ()
{
    typeset index indexes section mpath page=$1
    typeset -i i=0 NIndex=0

    for mpath in "${patharr[@]}"; do
        if [ -r $mpath/index ]; then
            indexes="$indexes $mpath/index"
            let NIndex+=1
        fi
    done
    [ -z "$indexes" ] && return
    # Make grep give filename
    [ NIndex -lt 2 ] && indexes="$indexes /dev/null"
    # set positional parameters to
    # indexfile:searchname pagename section ...
    # e.g.
    # /usr/man/index:FP_OFF Routines DOS
    set -- `grep "^$page[       ]" $indexes`
    while [ $# -gt 2 ]; do
        FileNames[i]=${1%%index*}cat$3/$2.$3
        Sections[i]=$3
        shift 3
        let i+=1
    done
}

# Finds all sections that man page $1 is in by searching each man directory
# in the order given in patharr[],
# and puts them in the the global array Sections[].  
# The filename of each page is put in FileNames[] with the same index.
# Global vars used:
# patharr[] MANPATH directories.
FindSectionsInDirs ()
{
    local page=$1 mpath AllPaths Path
    typeset -i i

    for mpath in "${patharr[@]}"; do
        AllPaths="$AllPaths $mpath/cat[0-9]*/$page.* $mpath/man[0-9]*/$page.*"
    done

    i=0
    for Path in $AllPaths; do
        istrue $debug && echo Path = $Path
        case "$Path" in
        *\*)    ;;
        *)
            # Remove compressed-file suffix to make FileNames be the same
            # as it is when built by FindSectionsInIndex()
            FileNames[i]=${Path%.[zZ]}
            Path=${Path%/*}
            Sections[i]=${Path##*/*.}
            let i+=1 ;;
        esac
    done
}

# FindSection: display man page.
# Uses ordarr[] (built from $ORDER) to display the version of the man
# page that occurs first in $ORDER.
# Sections[] gives the sections that a man page was found in.
# If the global variable "exist" is set to 1, nothing is displayed;
# the function instead returns zero if a page is found, nonzero if not.
# The filename of each page is in FileNames[] with the same index.
# Global vars used:
# Sections[], FileNames[], ordarr[]
FindSection ()
{
    typeset -i NumPages i foundsec
    local section OtherSec filename NPAGER=$PAGER POpt page=$1 Pat
    local PageFile

    NumPages=${#Sections[*]}    # Number of versions of man page found.
    isfalse $NumPages && return 1 
    case "$PAGER" in
    *less)      Popt="-p$page" ;;
    esac

    # For each section in ORDER, determine if any man page was found in
    # that section
    for section in "${ordarr[@]}"; do
        i=0
        foundsec=0
        while [ $i -lt $NumPages ]; do
            if [ "${Sections[i]}" = $section ]; then
                # Found a man page from this section of ORDER
                filename=${FileNames[i]}
                if [ -z "$PageFile" ]; then
                    PageFile=$filename
                else
                    if istrue $foundsec; then
                        OtherSec="$OtherSec$page(${filename%/*/*} $section) "
                    else
                        OtherSec="$OtherSec$page($section) "
                    fi
                fi
                foundsec=1
                istrue $exist && return
            fi
            let i+=1
        done
    done
    # No pages with the specified section found.
    [ -z "$PageFile" ] && return 1
    # Return if all we want to know is whether the man page exists.
    [ "$exist" = 1 ] && return 0
    if [ -z "$OtherSec" ]; then
        NPAGER="exec $PAGER"
    fi
    if [ -r $PageFile ]; then
        $NPAGER $POpt $PageFile
    elif [ -r $PageFile.z ]; then
        pcat $PageFile.z | $NPAGER $POpt
    elif [ -r $PageFile.Z ]; then
        zcat $PageFile.Z | $NPAGER $POpt
    elif [ -f $PageFile.gz ]; then
        gzip -dc $PageFile.gz | $NPAGER $POpt
    else
        echo "$PageFile: cannot open." 1>&2
        OtherSec=
        unset Sections[i]
        let i+=1
        continue
    fi
    echo "See also $OtherSec"
    exit 0
}

phelp()
{
echo "$name: print man pages.
$name locates and prints the specified manual pages from the online UNIX
documentation.
$Usage
Options:
-e: Determine whether the specified man page exists.  Nothing is printed;
    $0 exits with a zero status if the page exists and a nonzero status if
    it does not.
-h: Print this help."
}

# main program

typeset -i exist=0 debug=0

name=${0##*/}
Usage="Usage: $name [-eh] [[manpath] section] command-name"

while getopts :hex opt; do
    case $opt in
    h) phelp; exit 0;;
    e) exist=1 ;;
    x) debug=1 ;;
    +?) echo "$name: options should not be preceded by a '+'." 1>&2; exit 2;;
    ?) 
        echo "$name: $OPTARG: bad option.  Use -h for help." 1>&2 ; exit 2 ;;
    esac
done
 
# remove args that were options
shift $((OPTIND-1))

if [ $# -lt 1 ]; then
    echo -e "$Usage\nUse -h for help." 1>&2
    exit
fi

P=$PAGER
O=1:n:l:6:8:2:3:4:5:7:p:o
T=$TERM
M=${MANPATH:-/usr/local/man:/usr/man}
[ -f /etc/default/man ] && . /etc/default/man
[ -n "$P" ] && PAGER=$P
[ -n "$O" ] && ORDER=$O
[ -n "$T" ] && TERM=$T
[ -n "$M" ] && MANPATH=$M

case $# in
0)  echo "No man page specified." ; exit 1;;
1)  page=$1;;
2)  ORDER=$(echo $1 | tr a-z A-Z) ; page=$2;;
3)  MANPATH=$1 
    [ -n "$2" ] && ORDER=$(echo $2 | tr a-z A-Z)
    page=$3;;
*)  echo "Too many arguments."; exit 1;;
esac

aargs=("$@")
[ ! -t 0 ] && PAGER=cat

OIFS=$IFS
IFS=:
patharr=($MANPATH)
i=0
for d in $MANPATH; do
    for sec in $ORDER; do
        ordarr[i]=$d/cat${sec}
        let i+=1
        ordarr[i]=$d/man${sec}
        let i+=1
    done
done
IFS=$OIFS

istrue $debug && echo patharr = "${patharr[@]}"

# if less or more is being used, remove multiple blank lines
export LESS="-s $LESS"
export MORE="-s $MORE"

# Try using index
FindSectionsInIndex "$page"
# Exit 0 if a page was found and we're just testing for existence.
FindSection "$page" && exit 0

# Try searching directories
unset Sections[*]
FindSectionsInDirs "$page"
FindSection "$page" && exit 0

istrue $exist && exit 1

# Try using man
# If using more or less, make man run faster by letting more or less compress
# multiple blank lines instead of rmb
#case "$PAGER" in
#*more|*less)   manopt=-b;;
#esac

#cmd=(man $manopt -p$PAGER "${aargs[@]}")
export PAGER
cmd=(man $manopt "${aargs[@]}")
istrue $debug && echo "$name: running ${cmd[*]}" 1>&2
exec "${cmd[@]}"