如何在BASH中打印整行

Question

我刚开始使用bash脚本，我一直试图打印出整行代码，但却找不到工作的方法。

这是我的密码

#!/bin/bash
MOTD=`cat /etc/motd | awk '{print $1}'`
if [ "$MOTD" = "WARNING" ]
then
    echo "Audit Criteria: Warning banner exist."
    echo "Vulnerability: No."
    echo "Details: $MOTD "
else
    echo "Audit Criteria: Warning banners does not exist."
    echo "Vulnerability: Yes."
    echo "Details: $MOTD "
fi

我的产出是：

Audit Criteria: Warning banner exist.
Vulnerability: No.
Details: WARNING:

详细信息中只出现了“警告”，而不是WARNING:Authorized uses only All activity may be monitored and reported.：

我相信问题在于

MOTD=`cat /etc/motd | awk '{print $1}'` 

和

if [ "$MOTD" = "WARNING" ]部件，我尝试过{print$0}，但仍然无法让它工作。

Answer 1

我想您想要的是/etc/motd的第一行，而不是第一个单词。如果是这样的话，请使用以下方法：

MOTD=$(head -1 /etc/motd)

然后进行字符串比较。

if [[ $MOTD == WARNING* ]; then

有关检查字符串是否包含bash中的特定子字符串的更多信息，您可以检查String contains in bash。

Answer 2

也许用awk做整件事会更简单些：

awk 'NR==1{
    if($1=="WARNING") {
        print "Audit Criteria: Warning banner exists."
        print "Vulnerability: No."
    }
    else { 
        print "Audit Criteria: Warning banner does not exist."
        print "Vulnerability: Yes."
    }
    print "Details: " $0
    exit
}' /etc/motd

块末尾的条件NR==1和exit意味着只处理文件的第一行。

上面的代码与bash脚本非常相似，但是可以使用变量使其更短：

awk 'NR==1{if($1=="WARNING"){b="exists";v="No"}else{b="does not exist";v="Yes"}
printf "Audit Criteria: Warning banner %s.\nVulnerability: %s.\nDetails: %s\n",b,v,$0
exit}' /etc/motd

Answer 3

您只使用变量MOTD，而且它只有值警告。

#!/bin/bash

MOTD=`cat /etc/motd | awk '{print $1}'`    
if [ "$MOTD" = "WARNING" ]    
then
    echo "Audit Criteria: Warning banner exist."        
    echo "Vulnerability: No."       
    echo "Details: `cat /etc/motd` "    
else        
    echo "Audit Criteria: Warning banners does not exist."      
    echo "Vulnerability: Yes."      
    echo "Details: `cat /etc/motd`"    
fi

或者，如果在/etc/motd中有多行，并且只需要打印一行的话。

#!/bin/bash

MOTDL=`grep WARNING /etc/motd`
MOTD=`cat /etc/motd | awk '{print $1}'`    
if [ "$MOTD" = "WARNING" ]    
then
    echo "Audit Criteria: Warning banner exist."        
    echo "Vulnerability: No."       
    echo "Details: $MOTDL "    
else        
    echo "Audit Criteria: Warning banners does not exist."      
    echo "Vulnerability: Yes."      
    echo "Details: $MOTDL"    
fi