使用 shell 脚本将行附加到 /etc/hosts 文件

问题描述 投票：0回答：8

我有一个新的 Ubuntu 12.04 VPS。我正在尝试编写一个安装脚本来完成整个 LAMP 安装。我遇到问题的地方是在 

/etc/hosts
文件中附加一行。我当前的主机文件如下所示：

127.0.0.1       localhost Venus

# The following lines are desirable for IPv6 capable hosts
::1     ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

我希望它看起来像这样：

127.0.0.1       localhost Venus
192.241.xx.xx  venus.example.com venus

# The following lines are desirable for IPv6 capable hosts
::1     ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

我使用附加（

sed
）命令尝试了各种
\a
命令。由于某种原因，Ubuntu 要么只是在终端中回显 
hosts
文件的内容，要么什么都不做。如何使用 bash 脚本将第二行正确插入到文件中？

linux bash shell ubuntu sed
8个回答
69
投票

确保使用 

-i
的 
sed
选项。

-i[SUFFIX], --in-place[=SUFFIX]
  edit files in place (makes backup if extension supplied)

sed -i "2i192.241.xx.xx  venus.example.com venus" /etc/hosts

否则，

echo "192.241.xx.xx  venus.example.com venus" >> /etc/hosts

会在文件末尾追加该行，这可以按您的预期工作。

50
投票

如果您使用的是 mac 或者您需要 sudo 权限，请尝试以下操作：

sudo -- sh -c -e "echo '192.34.0.03   subdomain.domain.com' >> /etc/hosts";

它仍然会要求您输入密码。

@kainjow 的替代方式

echo '192.34.0.03 subdomain.domain.com' | sudo tee -a /etc/hosts
38
投票

插入/更新条目

如果您想使用 bash 以编程方式插入/更新主机条目，这是我为此编写的脚本：

#!/bin/bash

# insert/update hosts entry
ip_address="192.168.x.x"
host_name="my.hostname.example.com"
# find existing instances in the host file and save the line numbers
matches_in_hosts="$(grep -n $host_name /etc/hosts | cut -f1 -d:)"
host_entry="${ip_address} ${host_name}"

echo "Please enter your password if requested."

if [ ! -z "$matches_in_hosts" ]
then
    echo "Updating existing hosts entry."
    # iterate over the line numbers on which matches were found
    while read -r line_number; do
        # replace the text of each line with the desired host entry
        sudo sed -i '' "${line_number}s/.*/${host_entry} /" /etc/hosts
    done <<< "$matches_in_hosts"
else
    echo "Adding new hosts entry."
    echo "$host_entry" | sudo tee -a /etc/hosts > /dev/null
fi

该脚本旨在与 OS X 一起使用，但只需稍加调整也可以在 Linux 上运行。

5
投票
echo "127.0.0.1 localhost `hostname`">./temp_hosts
echo "192.241.xx.xx  venus.example.com">>./temp_hosts
cat /etc/hosts |tail -n +2 >>./temp_hosts
cat ./temp_hosts > /etc/hosts
rm ./temp_file
2
投票

我应该指出，

sed
（stream编辑器）实际上并不是用于编辑文件，尽管它可以用来编辑文件。 （标准 sed 没有用于写入标准输出以外的内置机制。）更合适的工具是 
ed
。

以下 ed 脚本表示“找到包含（诚然很草率）正则表达式 /127.0.0.1/ 的行并附加到下一行。” （唯一的句点告诉 ed 停止追加。）

ed /etc/hosts <<-'EOF'
    /127.0.0.1/a
    192.241.xx.xx  venus.example.com
    .
    wq
EOF

也就是说，您实际上可以非常简单地将这一行附加到 /etc/hosts 文件的end：

echo '192.241.xx.xx  venus.example.com' >> /etc/hosts
1
投票

您可以使用

sed
，例如：

sed '/Venus/ a\  
192.241.xx.xx  venus.example.com venus' /etc/hosts
0
投票

我开发了一个用户友好的脚本，可以轻松地在主机文件中添加、删除和列出 IP 地址和主机名：

#!/bin/bash
# Created by Mohamad Hamouday
# Date: 2023-12-05
# Purpose: A script to add, remove, and list entries in the hosts file


# Function to add an entry to the hosts file
add_entry() {
    # Get user input for IP address and server name
    read -p "Enter IP address: " ip_address
    read -p "Enter server name: " server_name

    # Check if the input is not empty
    if [ -z "$ip_address" ] || [ -z "$server_name" ]; then
        echo "IP address and server name cannot be empty."
        exit 1
    fi

    # Append the entry to the hosts file
    echo "$ip_address $server_name" >> /etc/hosts

    echo "Entry added to /etc/hosts: $ip_address $server_name"
}

# Function to remove an entry from the hosts file
remove_entry() {
    # Get user input for IP address or server name to remove
    read -p "Enter IP address or server name to remove: " entry_to_remove

    # Check if the input is not empty
    if [ -z "$entry_to_remove" ]; then
        echo "Entry cannot be empty."
        exit 1
    fi

    # Check if the entry exists in the hosts file
    if grep -q "$entry_to_remove" /etc/hosts; then
        # Remove the entry from the hosts file using sed
        sed -i.bak -e "/$entry_to_remove/d" /etc/hosts

        echo "Entry removed from /etc/hosts: $entry_to_remove"
    else
        echo "Entry does not exist in /etc/hosts: $entry_to_remove"
    fi
}


# Function to list all active entries in the hosts file
list_entries() {
    echo "Non-commented entries in /etc/hosts:"
    grep -E -v '^\s*#' /etc/hosts
}


# Check if the script is executed with root privileges
if [[ $EUID -ne 0 ]]; then
   echo "This script must be run as root."
   exit 1
fi

# Display menu for user choice
echo "1. Add entry"
echo "2. Remove entry"
echo "3. List entries"
read -p "Enter your choice (1, 2, or 3): " choice

case $choice in
    1)
        add_entry
        ;;
    2)
        remove_entry
        ;;
    3)
        list_entries
        ;;
    *)
        echo "Invalid choice. Exiting."
        exit 1
        ;;
esac

要执行它，只需运行：

sudo sh scriptname.sh
-2
投票

使用 root 访问权限尝试此操作。

 public void edithost() {
    sudo("echo " + "192.168.43.1     www.openrap.com openrap" + " >> /etc/hosts");
    sudo("echo " + "192.168.43.1  openrap.com openrap" + " >> /etc/hosts");
    sudo("echo " + "192.168.2.144  www.openrap.com openrap" + " >> /etc/hosts");
    sudo("echo " + "192.168.2.144  openrap.com openrap" + " >> /etc/hosts");
}

sudo 获得超级用户权限

public static void sudo(String... strings) {
    try {
        Process su = Runtime.getRuntime().exec("su");
        DataOutputStream outputStream = new DataOutputStream(su.getOutputStream());

        for (String s : strings) {
            outputStream.writeBytes(s + "\n");
            outputStream.flush();
        }

        outputStream.writeBytes("exit\n");
        outputStream.flush();
        try {
            su.waitFor();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        outputStream.close();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

这会将这些行附加到 android 中的主机

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