Linuxdoc Linux Questions
Click here to ask our community of linux experts!
Custom Search
Next Previous Contents

11. The msinfo.sh script

This shell script analyses the boot sector of the given partition and displays some information along with the "Total Special Sectors" in a message box. It assumes that the filesystem on the given partition is a FAT16. If not, it will print an error message and exit. Invoke it as

 
# msinfo <partition name> 
 

To run this script, you will need the "dialog" program that displays dialog boxes. You can get it from here.

#!/bin/sh 
# 
# msinfo.sh           This shell script displays the boot sector of the 
#                     given partition.
# 
# Author:             Rahul U. Joshi 
# 
# Modifications       Removed the use of expr and replaced it by the let 
#                     command. 
# 
# ------------------------------------------------------------------------
# This program is a free software, you can redistribute it and/or modify
# it under the eterms of the GNU General Public Liscence as published by
# the Free Software Foundation; either version 2 or (at your option) any
# later version.
#
# This program is being distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY without even the implied warranty of
# MERCHANTIBILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
# Public Liscence for more details.
# -------------------------------------------------------------------------
 
 
# check for command line arguments 
if [ $# -ne 1 ]; then 
   echo "Usage: msinfo <partition name>" 
   exit 1 
fi 
 
# check whether the input name is a block device 
if [ ! -b $1 ]; then 
   echo "msinfo: $1 is not a block device" 
   exit 1 
fi 
 
# create two temporary files for use 
TMPFILE=`mktemp -q /tmp/$0.XXXXXX` 
if [ $? -ne 0 ]; then 
    echo "msinfo: Can't create temp file, exiting..." 
    exit 1 
fi 
 
TXTFILE=`mktemp -q /tmp/$0.XXXXXX` 
if [ $? -ne 0 ]; then 
   echo "msinfo: Can't create temp file, exiting..." 
   rm -f $TMPFILE 
   exit 1 
fi 
 
backtitle="`printf "%78s" "msinfo, Information about FAT16 filesystem -- Rahul Joshi"`" 
 
dialog --title "Boot sector of $1" --backtitle "$back_title" \ 
       --infobox "\nAnalysing boot sector for $1\nPlease wait..."  14 60 
 
# truncate TXTFILE to zero length 
echo > $TXTFILE 
 
# get Formatting DOS version 
dd 2>/dev/null if=$1  bs=1 count=8 skip=3 | dd 2>/dev/null of=$TMPFILE 
printf >>$TXTFILE "%30s : %s\n" "Formatting DOS version" "`cat $TMPFILE`" 
 
 
# get file system 
dd 2>/dev/null if=$1  bs=1 count=8 skip=54 | dd 2>/dev/null of=$TMPFILE 
printf >>$TXTFILE "%30s : %s\n" "Filesystem" "`cat $TMPFILE`" 
 
# check if filesystem in a FAT16 
if [ "`cat $TMPFILE`" != "FAT16   " ]; then 
  dialog --title "Boot sector of $1" --backtitle "$back_title" \
         --infobox  "\nCan't find a FAT16 filesystem on $1"  14 60 
  exit 2 
fi 
 
# get volume label in boot sector 
dd 2>/dev/null if=$1  bs=1 count=11 skip=43 | dd 2>/dev/null of=$TMPFILE 
printf >>$TXTFILE "%30s : %s\n" "Volume label in boot sector" "`cat $TMPFILE`" 
  
 
# get Sector size 
dd 2>/dev/null if=$1  bs=1 count=2 skip=11| od -An -tdS | dd 2>/dev/null of=$TMPFILE 
printf >>$TXTFILE "%30s : %d\n" "Sector size" `cat $TMPFILE` 
sector_size=`cat $TMPFILE` 
 
 
# get Reserved sectors 
dd 2>/dev/null if=$1  bs=1 count=2 skip=14| od -An -tdS | dd 2>/dev/null of=$TMPFILE 
printf >>$TXTFILE "%30s : %d\n" " Reserved sectors" `cat $TMPFILE` 
reserved_sectors=`cat $TMPFILE` 
 
 
# get FAT sectors 
dd 2>/dev/null if=$1  bs=1 count=1 skip=16| od -An -tdS | dd 2>/dev/null of=$TMPFILE 
fat_count=`cat $TMPFILE` 
 
dd 2>/dev/null if=$1  bs=1 count=2 skip=22| od -An -tdS | dd 2>/dev/null of=$TMPFILE 
sectors_per_fat=`cat $TMPFILE` 
 
# calculate the no of sectors allocated for FAT's 
let fat_sectors=fat_count*sectors_per_fat 
 
printf >>$TXTFILE "%30s : %u (%u x %u) \n" "FAT sectors" "$fat_sectors" \
        "$fat_count" "$sectors_per_fat" 
 
 
# get root directory sectors 
dd 2>/dev/null if=$1  bs=1 count=2 skip=17| od -An -tdS | dd 2>/dev/null of=$TMPFILE 
root_sectors=`cat $TMPFILE` 
 
# calculate the no of sectors allocated for root directory 
let root_sectors=root_sectors*32/sector_size 
 
printf >>$TXTFILE "%30s : %u\n" "Root directory sectors" "$root_sectors" 
 
 
# get Total special sectors 
let total=reserved_sectors+fat_sectors+root_sectors 
printf >>$TXTFILE "%30s : %u\n" "Total special sectors" "$total" 
 
 
# display the information
dialog --title "Boot sector of $1"  --backtitle "$back_title"  --msgbox "`cat $TXTFILE`" 14 60 
  
# delete temporary files 
rm -f $TMPFILE 
rm -f $TXTFILE 
 
# end of msinfo.sh 


Next Previous Contents