1 綜合
[root@localhost script]# cat >nopwd
#/bin/bash
echo "no passwd user are :"
echo $(cat /etc/shadow | grep "!!" | awk 'BEGIN { FS=":" }{print $1}')
[root@localhost script]# bash nopwd
no passwd user are:
nscd vcsa rpc mailnull smmsp pcap ntp dbus avahi sshd rpcuser nfsnobody haldaemon avahi-autoipd oprofile xfs gdm sabayon postfix ldap mysql
2 echo
[root@localhost script]# cat >user
#!/bin/bash
echo "hello,$USER"
echo
echo "today 's date is `date`"
echo
echo "the user is :"
who
echo
echo "this is `uname -s`"
echo
echo "that's all folks!"
[root@localhost script]# bash user
Hello, root
Today 's date is Wed Jan 1 12:07:27 CST 2014
the user is :
root :0 2013-12-27 18:04
root pts/1 2013-12-27 18:04 (:0)
root pts/2 2014-01-01 11:17 (192.168.1.109)
this is Linux
that's all folks!
3 case
[root@localhost script]# cat >yesno
#!/bin/bash
echo "enter [y/n]:"
read a
case $a in
y|Y|yes|YES)
echo "you enter $a"
;;
n|N|no|NO)
echo "you enter $a"
;;
*)
echo "error"
;;
esac
[root@localhost script]# bash yesno
enter [y/n]:
error
[root@localhost script]# bash yesno
enter [y/n]:
y
you enter y
[root@localhost script]# bash yesno
enter [y/n]:
n
you enter n
4 case
[root@localhost script]# cat >1-5
#!/bin/bash
echo "please enter a number from 1 to 5:"
read num
case $num in
1) echo "you enter is 1" ;;
2) echo "you enter is 2" ;;
3) echo "you enter is 3" ;;
4) echo "you enter is 4" ;;
5) echo "you enter is 5" ;;
*) echo "error" ;;
esac
[root@localhost script]# bash 1-5
please enter a number from 1 to 5:
4
you enter is 4
[root@localhost script]# bash 1-5
please enter a number from 1 to 5:
3
you enter is 3
5 read
[root@localhost script]# cat >read
#!/bin/bash
echo "please enter your first name and last name"
read first last
echo "your first name is $first"
echo "your last name is $last"
[root@localhost script]# bash read
please enter your first name and last name
feng
your first name is feng
your last name is
[root@localhost script]# bash read
please enter your first name and last name
feng yuan
your first name is feng
your last name is yuan
6 for
[root@localhost script]# cat >for
#!/bin/bash
f=1
for a in `seq 1 10`
do
f=`expr $f \* $a`
done
echo "10! = $f"
[root@localhost script]# bash for
10! = 3628800
7 while
[root@localhost script]# cat >while
#!/bin/bash
while [ "$var" != "end" ]
do
echo -n "please input a number:"
read var
if [ "$var" = "end" ]
then
break
fi
echo "var is $var"
done
[root@localhost script]# bash while
please input a number:3
var is 3
please input a number:2
var is 2
please input a number:32
var is 32
please input a number:end
8 login
[root@localhost script]# bash login
login:fj
passwd:ie
input is error
[root@localhost script]# bash login
login:what
passwd:who
the host and passwd is right
[root@localhost script]# cat login
#!/bin/bash
echo -n "login:"
read name
echo -n "passwd:"
read pwd
if [ $name = "what" -a $pwd = "who" ]
then
echo "the host and passwd is right"
else
echo "input is error"
fi
9 compare
[root@localhost script]# bash compare
please input two number
87
43
no.1 > no.2
[root@localhost script]# cat compare
#!/bin/bash
echo "please input two number"
read a
read b
if [ $a -eq $b ]
then echo "no.1 = no.2"
elif [ $a -gt $b ]
then echo "no.1 > no.2"
else echo "no.1 < no.2"
fi
10
要求輸入字符必須只包含字母。如果不用函數實現這一點，要寫大量腳本。使用函數可
以將重複腳本刪去。這裏用awk語言測試字符。以下是取得只有小寫或大寫字符的測試函數。
首先設置變量$1爲一有意義的名字，然後用awk測試整個傳送記錄只包含字母，此命令輸
出（1爲非字母，空爲成功）保存在變量_LETTERS_ONLY中。
然後執行變量測試，如果爲空，則爲成功，如果有值，則爲錯誤。基於此項測試，返回
碼然後被執行。在對腳本的函數調用部分進行測試時，使用返回值會使腳本清晰易懂。
使用i f語句格式測試函數功能
如果有錯誤，可編寫一個函數將錯誤反饋到屏幕上。
函數name_error用於顯示所有無效輸入錯誤。使用特殊變量$@顯示所有參數，這裏爲變
量FNAME和SNAME值。
注意每個輸入的while循環，這將確保不斷提示輸入直至爲正確值，然後跳出循環。當然，
實際腳本擁有允許用戶退出循環的選項，可使用適當的遊標，正像控制0長度域一樣。
運行上述腳本的情況如下：
[root@localhost script]# cat fun-name
#!/bin/bash
char_name() {
_LETTERS_ONLY=$1
_LETTERS_ONLY=`echo $1|awk '{if($0~/[^a-zA-Z]/) print "1"}'`
if [ "$_LETTERS_ONLY" != "" ]
then return 1
else return 0
fi
}
name_error() {
echo "$@ contains errors,it must be contain only letters"
}
while :
do
echo -n "what is your first name :"
read F_NAME
if char_name $F_NAME
then break
else name_error $F_NAME
fi
done
while :
do
echo -n "what is your surname: "
read S_NAME
if char_name $S_NAME
then break
else name_error $S_NAME
fi
done
[root@localhost script]# bash fun-name
what is your first name :eie
what is your surname: lsls9
lsls9 contains errors,it must be contain only letters
what is your surname: kfj#
kfj# contains errors,it must be contain only letters
what is your surname: feifj