Shell Script To Rename File Name To Lowercase

#!/bin/bash
# Write a shell script that changes the name of the file passed as argument
# to lowercase.
# -------------------------------------------------------------------------
# Copyright (c) 2003 nixCraft project
# This script is licensed under GNU GPL version 2.0 or above
# -------------------------------------------------------------------------
# This script is part of nixCraft shell script collection (NSSC)
# Visit http://bash.cyberciti.biz/ for more information.
# -------------------------------------------------------------------------

file="$1"
if [ $# -eq 0 ]
then
echo "$(basename $0) file"
exit 1
fi

if [ ! $file ]
then
echo "$file not a file"
exit 2
fi

lowercase=$(echo $file | tr '[A-Z]' '[a-z]'])

if [ -f $lowercase ]
then
echo "Error - File already exists!"
exit 3
fi

# change file name
/bin/mv $file $lowercase

Shell Script To Read File Date - Last Access / Modification Time

#!/bin/bash
# Write a shell script to display / read file date / time in following format:
# Time of last access
# Time of last modification
# Time of last change
# -------------------------------------------------------------------------
# Copyright (c) 2007 nixCraft project
# This script is licensed under GNU GPL version 2.0 or above
# -------------------------------------------------------------------------
# This script is part of nixCraft shell script collection (NSSC)
# Visit http://bash.cyberciti.biz/ for more information.
# -------------------------------------------------------------------------
FILE="$1"

# make sure we got file-name as command line argument
if [ $# -eq 0 ]
then
echo "$0 file-name"
exit 1
fi

which stat > /dev/null

# make sure stat command is installed
if [ $? -eq 1 ]
then
echo "stat command not found!"
exit 2
fi

# make sure file exists
if [ ! -e $FILE ]
then
echo "$FILE not a file"
exit 3
fi

# use stat command to get info
echo "Time of last access : $(stat -c %x $FILE)"
echo "Time of last modification : $(stat -c %y $FILE)"
echo "Time of last change : $(stat -c %z $FILE)"

Shell script to find all programs and scripts with setuid bit set on

#!/bin/bash
# Shell script to find all programs and scripts with setuid bit set on.
# If your system ever cracked (aka hacked) then system has this kind of binary
# installed; besides the normal setuuid scripts/programs
#
# *TIP*
# User directory /home and webroots such as /www canbe mounted with
# nosuid option.
#
# Copyright (c) 2005 nixCraft project.
# This script is licensed under GNU GPL version 2.0 or above
# For more info, please visit:
# http://cyberciti.biz/shell_scripting/bmsinstall.php
# -------------------------------------------------------------------------
# This script is part of nixCraft shell script collection (NSSC)
# Visit http://bash.cyberciti.biz/ for more information.
# -------------------------------------------------------------------------
#SPATH="/usr/local/etc/bashmonscripts"
#INITBMS="$SPATH/defaults.conf"
#[ ! -f $INITBMS ] && exit 1 || . $INITBMS

[ $# -eq 1 ] && : || die "Usage: $($BASENAME $0) directory" 1

DIRNAME="$1"
$FIND $DIRNAME -xdev -type f -perm +u=s -print

Shell script to find all world-writable files and directories on Linux / UNIX system

#!/bin/bash
# Shell script to find all world-writable files and directories on Linux or
# FreeBSD system
#
# TIP:
# Set 'umask 002' so that new files created will not be world-writable
# And use command 'chmod o-w filename' to disable world-wriable file bit
#
# Copyright (c) 2005 nixCraft project
# This script is licensed under GNU GPL version 2.0 or above
# For more info, please visit:
# http://cyberciti.biz/shell_scripting/bmsinstall.php
# -------------------------------------------------------------------------
# This script is part of nixCraft shell script collection (NSSC)
# Visit http://bash.cyberciti.biz/ for more information.
# -------------------------------------------------------------------------
#SPATH="/usr/local/etc/bashmonscripts"
#INITBMS="$SPATH/defaults.conf"
#[ ! -f $INITBMS ] && exit 1 || . $INITBMS

[ $# -eq 1 ] && : || die "Usage: $($BASENAME $0) directory" 1

DIRNAME="$1"
$FIND $DIRNAME -xdev -perm +o=w ! \( -type d -perm +o=t \) ! -type l -print

Monitor UNIX / Linux Server Disk Space with Shell Script

#!/bin/sh
# Shell script to monitor or watch the disk space
# It will send an email to $ADMIN, if the (free avilable) percentage
# of space is >= 90%
# -------------------------------------------------------------------------
# Copyright (c) 2005 nixCraft project
# This script is licensed under GNU GPL version 2.0 or above
# -------------------------------------------------------------------------
# This script is part of nixCraft shell script collection (NSSC)
# Visit http://bash.cyberciti.biz/ for more information.
# ----------------------------------------------------------------------
# Linux shell script to watch disk space (should work on other UNIX oses )
# SEE URL: http://www.cyberciti.biz/tips/shell-script-to-watch-the-disk-space.html
# set admin email so that you can get email
ADMIN="me@somewher.com"
# set alert level 90% is default
ALERT=90
df -H | grep -vE '^Filesystem|tmpfs|cdrom' | awk '{ print $5 " " $1 }' | while read output;
do
#echo $output
usep=$(echo $output | awk '{ print $1}' | cut -d'%' -f1 )
partition=$(echo $output | awk '{ print $2 }' )
if [ $usep -ge $ALERT ]; then
echo "Running out of space \"$partition ($usep%)\" on $(hostname) as on $(date)" |
mail -s "Alert: Almost out of disk space $usep" $ADMIN
fi
done

Shell Script accept password using read commnad

#!/bin/bash
# Script accept password using read commnad
# Not *very secure*, this script is for learning purpose only
# -------------------------------------------------------------------------
# This script is part of nixCraft shell script collection (NSSC)
# Visit http://bash.cyberciti.biz/ for more information.
# -------------------------------------------------------------------------
PASS="abc123"
read -s -p "Password: " mypassword
echo ""
[ "$mypassword" == "$PASS" ] && echo "Password accepted" || echo "Access denied"

Script to update user password in batch mode

#!/bin/bash
# Script to update user password in batch mode
# You must be a root user to use this script
# -------------------------------------------------------------------------
# Copyright (c) 2005 nixCraft project
# This script is licensed under GNU GPL version 2.0 or above
# -------------------------------------------------------------------------
# This script is part of nixCraft shell script collection (NSSC)
# Visit http://bash.cyberciti.biz/ for more information.
# ----------------------------------------------------------------------
# /root is good place to store clear text password
FILE="/root/batch.passwd"

# get all non-root user account
# By default on most linux non-root uid starts
# from 1000
USERS=$(awk -F: '{ if ( $3 > 1000 ) print $1}' /etc/passwd)

# create file with random password
echo "Generating file, please wait..."

# overwrite file, this is bash specific a better solution is cat > $FILE
>$FILE

for u in $USERS
do
p=$(pwgen -1 -n 8) # create random password
echo "$u:$p" >> $FILE # save USERNAME:PASSWORD pair
done
echo ""
echo "Random password and username list stored in $FILE file"
echo "Review $FILE file, once satisfied execute command: "
echo "chpasswd < $FILE"

# Uncomment following line if you want immediately update all users password,
# be careful with this option, it is recommended that you review $FILE first
# chpasswd < $FILE

Shell Script to read source file and copy it to target file

#!/bin/bash
# Shell to read source file and copy it to target file. If the file
# is copied successfully then give message 'File copied successfully'
# else give message 'problem copying file'
# -------------------------------------------------------------------------
# Copyright (c) 2005 nixCraft project
# This script is licensed under GNU GPL version 2.0 or above
# -------------------------------------------------------------------------
# This script is part of nixCraft shell script collection (NSSC)
# Visit http://bash.cyberciti.biz/ for more information.
# -------------------------------------------------------------------------

echo -n "Enter soruce file name : "
read src
echo -n "Enter target file name : "
read targ

if [ ! -f $src ]
then
echo "File $src does not exists"
exit 1
elif [ -f $targ ]
then
echo "File $targ exist, cannot overwrite"
exit 2
fi

# copy file
cp $src $targ

# store exit status of above cp command. It is use to
# determine if shell command operations is successful or not
status=$?

if [ $status -eq 0 ]
then
echo 'File copied successfully'
else
echo 'Problem copuing file'
fi

Menu Driven Shell Script

A menu driven Shell script which has following options
# Contents of /etc/passwd
# List of users currently logged
# Prsent handling directory
# Exit
# As per option do the job
# -----------------------------------------------
# Copyright (c) 2005 nixCraft project
# This script is licensed under GNU GPL version 2.0 or above
# -------------------------------------------------------------------------
# This script is part of nixCraft shell script collection (NSSC)
# Visit http://bash.cyberciti.biz/ for more information.
# -------------------------------------------------------------------------

while :
do
clear
echo " M A I N - M E N U"
echo "1. Contents of /etc/passwd"
echo "2. List of users currently logged"
echo "3. Prsent handling directory"
echo "4. Exit"
echo -n "Please enter option [1 - 4]"
read opt
case $opt in
1) echo "************ Conents of /etc/passwd *************";
more /etc/passwd;;
2) echo "*********** List of users currently logged";
who | more;;
3) echo "You are in $(pwd) directory";
echo "Press [enter] key to continue. . .";
read enterKey;;
4) echo "Bye $USER";
exit 1;;
*) echo "$opt is an invaild option. Please select option between 1-4 only";
echo "Press [enter] key to continue. . .";
read enterKey;;
esac
done

Script to convert numbers into equivalent words

#!/bin/bash
# Shell script to read a number and write the number in words. Use case
# control structure. For example 12 should be print as one two
# -------------------------------------------------------------------------
# Copyright (c) 2005 nixCraft project
# This script is licensed under GNU GPL version 2.0 or above
# -------------------------------------------------------------------------
# This script is part of nixCraft shell script collection (NSSC)
# Visit http://bash.cyberciti.biz/ for more information.
# -------------------------------------------------------------------------

echo -n "Enter number : "
read n

len=$(echo $n | wc -c)
len=$(( $len - 1 ))

echo "Your number $n in words : "
for (( i=1; i<=$len; i++ ))
do
# get one digit at a time
digit=$(echo $n | cut -c $i)
# use case control structure to find digit equivalent in words
case $digit in
0) echo -n "zero " ;;
1) echo -n "one " ;;
2) echo -n "two " ;;
3) echo -n "three " ;;
4) echo -n "four " ;;
5) echo -n "five " ;;
6) echo -n "six " ;;
7) echo -n "seven " ;;
8) echo -n "eight " ;;
9) echo -n "nine " ;;
esac
done

# just print new line
echo ""

Script To Count Number Of Files In Each Subdirectories

#!/bin/bash
# Write a script that will count the number of files in each of your subdirectories.
# -------------------------------------------------------------------------
# Copyright (c) 2001 nixCraft project
# This script is licensed under GNU GPL version 2.0 or above
# -------------------------------------------------------------------------
# This script is part of nixCraft shell script collection (NSSC)
# Visit http://bash.cyberciti.biz/ for more information.
# -------------------------------------------------------------------------

START=$HOME

# change your directory to command line if passed
# otherwise use home directory
[ $# -eq 1 ] && START=$1 || :

if [ ! -d $START ]
then
echo "$START not a directory!"
exit 1
fi

# use find command to get all subdirs name in DIRS variable
DIRS=$(find "$START" -type d)

# loop thought each dir to get the number of files in each of subdir
for d in $DIRS
do
[ "$d" != "." -a "$d" != ".." ] && echo "$d dirctory has $(ls -l $d | wc -l) files" || :
done

Finding ALL Superuser ( root ) Accounts under UNIX

Find all root power account using below command

grep -v -E "^#" /etc/passwd | awk -F: '$3 == 0 { print $1}'

Shell script for search for no password entries and lock all accounts

#!/bin/bash
# Shell script for search for no password entries and lock all accounts
# -------------------------------------------------------------------------
# Copyright (c) 2005 nixCraft project
# This script is licensed under GNU GPL version 2.0 or above
# -------------------------------------------------------------------------
# This script is part of nixCraft shell script collection (NSSC)
# Visit http://bash.cyberciti.biz/ for more information.
# -------------------------------------------------------------------------
# Set your email
ADMINEMAIL="admin@somewhere.com"

### Do not change anything below ###
#LOG File
LOG="/root/nopassword.lock.log"
STATUS=0
TMPFILE="/tmp/null.mail.$$"

echo "-------------------------------------------------------" >>$LOG
echo "Host: $(hostname), Run date: $(date)" >> $LOG
echo "-------------------------------------------------------" >>$LOG

# get all user names
USERS="$(cut -d: -f 1 /etc/passwd)"

# display message
echo "Searching for null password..."
for u in $USERS
do
# find out if password is set or not (null password)
passwd -S $u | grep -Ew "NP" >/dev/null
if [ $? -eq 0 ]; then # if so
echo "$u" >> $LOG
passwd -l $u #lock account
STATUS=1 #update status so that we can send an email
fi
done
echo "========================================================" >>$LOG
if [ $STATUS -eq 1 ]; then
echo "Please see $LOG file and all account with no password are locked!" >$TMPFILE
echo "-- $(basename $0) script" >>$TMPFILE
mail -s "Account with no password found and locked" "$ADMINEMAIL" < $TMPFILE
# rm -f $TMPFILE
fi

Note: http://bash.cyberciti.biz/security/script-to-lock-all-passwordless-accounts/