• curl -c cookie.txt URL: save cookies to cookie.txt
• curl -b cookie.txt URL: read cookie from cookie.txt and put into request
• curl -H 'User-Agent: FakeUA' URL: set HTTP header
• curl -I URL: show header only
• curl -L URL: follow 30x redirect
• curl -o new_name/-O URL: save response to file
• curl -X POST --data "data=xxx" URL: POST data to URL
• curl -w "@curl-format.txt" URL: format details of request, which you can use this to timing request:

➜ cat curl-format.txt
    time_namelookup:  %{time_namelookup}\n
       time_connect:  %{time_connect}\n
    time_appconnect:  %{time_appconnect}\n
      time_redirect:  %{time_redirect}\n
   time_pretransfer:  %{time_pretransfer}\n
 time_starttransfer:  %{time_starttransfer}\n
                    ----------\n
         time_total:  %{time_total}\n

➜ curl -w "@curl-format.txt" -o /dev/null -s https://fann.im
    time_namelookup:  0.015
       time_connect:  0.015
    time_appconnect:  0.329
      time_redirect:  0.000
   time_pretransfer:  0.329
 time_starttransfer:  0.377
                    ----------
         time_total:  0.377

而立。

7.

如果数据量小且不在服务中，可以直接修改表结构：

ALTER TABLE table_name ENGINE=InnoDB;

然后现实是需要迁移表的数据量往往很大，不好直接 ALTER。一个办法是导出-修改表结构-导入，需要修改的有表名，engine，导入后重命名新／旧表。需要注意的是 mysqldump 默认有 DROP TABLE 命令，需要去掉，不然导入时候会直接删掉旧表。

还有一个方法是按照旧表结构新建表，将数据从旧表导入新表：

CREATE TABLE innodb_table LIKE mytable;
ALTER TABLE innodb_table ENGINE=InnoDB;
INSERT INTO innodb_table SELECT * FROM mytable;

数据量大的话可以事务处理：

START TRANSACTION;
INSERT INTO innodb_table SELECT * FROM mytable WHERE id BETWEEN x AND y;
COMMIT;

数据验证完整后重命名：

RENAME TABLE mytable TO mytable_old, innodb_table TO mytable;
//DROP TABLE mytable_old;

• Converting Tables from MyISAM to InnoDB
• Converting big table from MyISAM to Innodb

XDG 是 X Desktop Group 的简称，现在叫 Freedesktop.org，致力于推动 *nix 桌面环境的标准规范化。其中 XDG Base Directory 定义了文件配置基本目录：

• $XDG_CONFIG_HOME 是配置文件目录，默认 $HOME/.config
• $XDG_DATA_HOME 是用户文件的基本保存目录，默认 $HOME/.local/share
• $XDG_DATA_DIRS 定义 $XDG_DATA_HOME 以外的文件基础目录，是一个有序目录集合，默认 /usr/local/share/:/usr/share/
• $XDG_CONFIG_DIRS 同理，是扩展的配置文件目录，默认 /etc/xdg，需要注意的是目录顺序很重要，$XDG_CONFIG_HOME 优先级最高
• $XDG_CACHE_HOME 缓存目录，默认 $HOME/.cache
• $XDG_RUNTIME_DIR 指定非必需运行时文件保存目录

Neovim 支持 XDG Base Directory，配置文件是 $HOME/.config/nvim/init.vim，shada 文件在 $HOME/.local/share/nvim.

via XDG Base Directory Specification

You can use OpenSSL to verify whether a SSL certificate and a key is matched:

openssl x509 -noout -in certificate.crt | openssl md5
openssl rsa -noout -in privateKey.key | openssl md5
openssl req -noout -in CSR.csr | openssl md5

If both commands return same hash, the certificate and key is matched.

You will be asked ‘Enter passphrase for key’ when doing SSH operation:

Enter passphrase for key ‘/Users/fannheyward/.ssh/id_rsa’:

On macOS you can fix this by ssh-add -K.

cd - can goto last directory that you just leave, - means $OLDPWD. This only support one directory.

pushd / popd / dirs works on multiple directories, as a directory stack:

pushd [dir1] # add dir to stack
popd [dir1] # pop dir from stack
dirs # list stack
dirs -c # cleanup stack

Ansible 是基于 SSH 的自动化配置管理和部署工具，更多请参考官方文档。

ansible -i hosts.ini all -m ping
ansible-playbook -i hosts.ini playbook.yaml

用 Ansible + Supervisor 部署／更新应用：

- hosts: server
  tasks:
  - name: check if exists
    stat: path=/path/to/app
    register: check_path
  - name: clone
    shell: git clone XXX && git checkout -b release
    when: check_path.stat.exists == false
  - name: pull
    shell: cd /path/to/app && git pull origin release
    when: check_path.stat.exists
  - name: is already running ?
    stat: path=/tmp/supervisord.pid
    register: supervisord_stat
  - name: restart
    command: supervisorctl -c supervisord.conf restart all
    args:
      chdir: /path/to/app
    when: supervisord_stat.stat.exists
  - name: start
    command: supervisord -c supervisord.conf
    args:
      chdir: /path/to/app
    when: supervisord_stat.stat.exists == false

• Ansible Galaxy
• An Ansible Tutorial
• iOS Dev Playbook
• Mac Development Ansible Playbook