8个实用的Shell脚本分享

done < hosts.allow 
for ((i=1;i<=${#hosts_allow[@]};i++)); do 
    echo ${hosts_allow[$i]} 
done 
echo "Done" 
[root@host ~]# ./readlines.sh 
127.0.0.2 
127.0.0.3 
127.0.0.4 
127.0.0.5 
127.0.0.6 
127.0.0.7 
127.0.0.8 
127.0.0.9 
Done 

【例子:007】简单正则表达式应用

[root@host ~]# cat regex.sh 
#!/bin/env sh 
#Filename: regex.sh 
regex="[A-Za-z0-9]{6}" 
if [[ $1 =~ $regex ]] 
then 
  num=$1 
  echo $num 
else 
  echo "Invalid entry" 
  exit 1 
fi 
[root@host ~]# ./regex.sh 123abc 
123abc 
 
#!/bin/env bash 
#Filename: validint.sh 
validint(){ 
    ret=`echo $1 | awk '{start = match($1,/^-?[0-9]+$/);if (start == 0) print "1";else print "0"}'` 
    return $ret 
} 
 
validint $1 
 
if [ $? -ne 0 ]; then 
    echo "Wrong Entry" 
    exit 1 
else 
    echo "OK! Input number is:" $1 
fi 

【例子:008】简单的按日期备份文件

#!/bin/bash 
 
NOW=$(date +"%m-%d-%Y")      # 当前日期 
FILE="backup.$NOW.tar.gz"    # 备份文件 
echo "Backing up data to /tmp/backup.$NOW.tar.gz file, please wait..."  #打印信息 
tar xcvf /tmp/backup.$NOW.tar.gz /home/ /etc/ /var       # 同时备份多个文件到指定的tar压缩文件中 
echo "Done..."