Bash EOF 技巧
文章目录
EOF适用场景：
- 命令行多行输出
- 脚本包装
- 类型配置文件
1. 命令行输出
$ cat << EOF > Hello > EOF Hello
2. 写入文本
cat << EOF >1.txt 111 222 333 EOF
复制终端是这样的。
cat << EOF >1.txt > 111 > 222 > 333 > EOF
回车后
$ cat 1.txt 111 222 333
3. 追加文本
cat << EOF >> 1.txt 444 555 666 EOF
查看1.txt内容
$ cat 1.txt 111 222 333 444 555 666
4. 覆盖文本
cat << EOF >1.txt aaa bbb ccc EOF
查看
$ cat 1.txt aaa bbb ccc
5. 自定义 EOF
cat << a > 1.txt 111 222 333 a
输出：
$ cat 1.txt 111 222 333
6. 另一种格式
cat > filename <<EOFcat << EOF > filename
cat > 1.txt <<EOF 123 456 789 EOF
查看
$ cat 1.txt 123 456 789
追加内容
cat >> 1.txt <<EOF abc def ghi EOF
查看内容
$ cat 1.txt 123 456 789 abc def ghi
7. 示例
7.1 配置文件
或者cat << EOF > /usr/local/mysql/my.cnf
cat > /usr/local/mysql/my.cnf << EOF [client] port = 3306 socket = /usr/local/mysql/var/mysql.sock [mysqld] port = 3306 socket = /usr/local/mysql/var/mysql.sock basedir = /usr/local/mysql/ datadir = /data/mysql/data pid-file = /data/mysql/data/mysql.pid user = mysql bind-address = 0.0.0.0 server-id = 1 sync_binlog=1 log_bin = mysql-bin [myisamchk] key_buffer_size = 8M sort_buffer_size = 8M read_buffer = 4M write_buffer = 4M sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES port = 3306 EOF
7.2 新建分区并挂载
$ cat auto_add_disk.sh #!/bin/bash fdisk /dev/sdb <<EOF n p 1 wq EOF /sbin/mkfs .ext4 /dev/sdb1 && /bin/mkdir -p /data && /bin/mount /dev/sdb1 /data echo 'LABEL=data_disk /data ext4 defaults 0 2' >> /etc/fstab
7.3 设置变量
$ sql=$(cat <<EOF SELECT foo, bar FROM db WHERE foo='baz' EOF ) $ echo -e "$sql"
7.4 输出脚本
cat <<EOF > print.sh #!/bin/bash echo \$PWD echo $PWD EOF
查看内容
$ cat print.sh #!/bin/bash echo $PWD echo /home/user
7.5 匹配输出
$ cat <<EOF | grep 'b' | tee b.txt > foo > bar > baz > EOF bar baz $ cat b.txt bar baz
7.6 json 文本
cat >> /etc/docker/daemon.json < EOF { "exec-opts": ["native.cgroupdriver=systemd"], "log-driver": "json-file", "log-opts": { "max-size": "100m" }, "registry-mirrors": [ "https://hub-mirror.c.163.com", "https://mirror.baidubce.com" ] } EOF
查看
$ cat /etc/docker/daemon.json { "exec-opts": ["native.cgroupdriver=systemd"], "log-driver": "json-file", "log-opts": { "max-size": "100m" }, "registry-mirrors": [ "https://hub-mirror.c.163.com", "https://mirror.baidubce.com" ] }
参考：
