REPL

REPL(Read Eval Print Loop:交互式解释器) 表示一个电脑的环境，类似 Window 系统的终端或 Unix/Linux shell，我们可以在终端中输入命令，并接收系统的响应。

交互式目录

[root@localhost ~]# ntpq
[root@localhost ~]# sqlite3
[root@localhost ~]# mysql -p
[root@localhost ~]# php -a
[root@localhost ~]# python
[root@localhost ~]# mail
[root@localhost ~]# yum shell
[root@localhost ~]# virsh
[root@localhost ~]# debugfs
[root@localhost ~]# gdb
[root@localhost ~]# ./redis-cli
[root@localhost ~]# ./mongo
[root@localhost ~]# bc
[root@localhost ~]# node(node.js)

[oracle@localhost ]$ sqlplus / as sysdba

[root@localhost ~]# ntpq
ntpq> peers
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
+gus.buptnet.edu 202.112.10.60     u           88.144   32.547   5.601
+ntp.verd.co.id  202.162.32.12     u          209.770    4.300 167.134
*ktdns.cdnetwork 131.107.13.100    u           70.834   33.196  20.738
ntpq> ?
ntpq commands:
:config          delay            mreadvar         readlist
addvars          exit             mrl              readvar
associations     help             mrv              rl
authenticate     host             ntpversion       rmvars
ntpq> q
[root@localhost ~]#

[root@localhost ~]# sqlite3
SQLite version 3.6.
Enter ".help" for instructions
Enter SQL statements terminated with a ";"
sqlite> .help
.backup ?DB? FILE      Backup DB (default "main") to FILE
.bail ON|OFF           Stop after hitting an error.  Default OFF
.databases             List names and files of attached databases
.dump ?TABLE? ...      Dump the database in an SQL text format
sqlite> .quit
[root@localhost ~]#

[root@84-monitor ~]# mysql -p
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is
Server version: 5.1. Source distribution
mysql> ?
mysql> quit
Bye
[root@-monitor ~]#

-bash-3.2$ sqlplus / as sysdba

SQL*Plus: Release 11.2.0.1. Production on Thu Feb  :: 

Copyright (c) , , Oracle.  All rights reserved.

Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.1. - 64bit Production
With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,
Data Mining and Real Application Testing options

SQL> ?

 HELP
 ----

 Accesses this command line help system. Enter HELP INDEX or ? INDEX
 for a list of topics.

 You can view SQL*Plus resources at
     http://www.oracle.com/technology/tech/sql_plus/
 and the Oracle Database Library at
     http://www.oracle.com/technology/documentation/

 HELP|? [topic]

SQL> quit
Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.1. - 64bit Production
With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,
Data Mining and Real Application Testing options
-bash-3.2$

[root@84-monitor ~]# php -a
Interactive shell

php >
php > b    tab两次
BadFunctionCallException  BadMethodCallException    base64_decode             base64_encode             base_convert              basename
bin2hex                   bind_textdomain_codeset   bindec                    bindtextdomain            bzclose                   bzcompress
bzdecompress              bzerrno                   bzerror                   bzerrstr                  bzflush                   bzread
bzwrite                   bzopen
php > b
php > quit
[root@-monitor ~]#

[root@84-monitor ~]# python
Python 2.6. (r266:, Jan  , ::)
[GCC 4.4.  (Red Hat 4.4.-)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> help
Type help() for interactive help, or help(object) for help about object.
>>> help()

Welcome to Python 2.6!  This is the online help utility.

If this is your first time using Python, you should definitely check out
the tutorial on the Internet at http://docs.python.org/tutorial/.

Enter the name of any module, keyword, or topic to get help on writing
Python programs and using Python modules.  To quit this help utility and
return to the interpreter, just type "quit".

To get a list of available modules, keywords, or topics, type "modules",
"keywords", or "topics".  Each module also comes with a one-line summary
of what it does; to list the modules whose summaries contain a given word
such as "spam", type "modules spam".

help> q

You are now leaving help and returning to the Python interpreter.
If you want to ask for help on a particular object directly from the
interpreter, you can type "help(object)".  Executing "help('string')"
has the same effect as typing a particular string at the help> prompt.
>>> exit()
[root@-monitor ~]#

[root@host02 ~]# mail
Heirloom Mail version 12.4 7/29/08.  Type ? for help.
"/var/spool/mail/root": 6 messages 1 unread
    1 Cron Daemon           Thu Nov  8 17:07  22/791   "Cron <root@8A_2> /usr/local/nagios/cache-bin/client.sh localhost"
>U  2 Cron Daemon           Thu Nov  8 17:08  22/790   "Cron <root@8A_2> /usr/local/nagios/cache-bin/client.sh localhost"

[root@84-monitor monitor]# yum shell
Loaded plugins: fastestmirror
Setting up Yum Shell
> ?
Usage: yum [options] COMMAND

[root@kvm1 qemu]# virsh
Welcome to virsh, the virtualization interactive terminal.

Type:  'help' for help with commands
       'quit' to quit

virsh # 

[root@104-c6 ~]# debugfs
debugfs 1.41.12 (17-May-2010)
debugfs:
debugfs:  help
Available debugfs requests:

show_debugfs_params, params
                         Show debugfs parameters
open_filesys, open       Open a filesystem
close_filesys, close     Close the filesystem
feature, features        Set/print superblock features
dirty_filesys, dirty     Mark the filesystem as dirty
init_filesys             Initialize a filesystem (DESTROYS DATA)
show_super_stats, stats  Show superblock statistics
ncheck                   Do inode->name translation
icheck                   Do block->inode translation
change_root_directory, chroot
                         Change root directory
change_working_directory, cd
                         Change working directory
list_directory, ls       List directory
show_inode_info, stat    Show inode information
dump_extents, extents, ex
                         Dump extents information
link, ln                 Create directory link
unlink                   Delete a directory link
mkdir                    Create a directory
rmdir                    Remove a directory
rm                       Remove a file (unlink and kill_file, if appropriate)
kill_file                Deallocate an inode and its blocks
clri                     Clear an inode's contents
freei                    Clear an inode's in-use flag

[root@localhost src]# ./redis-cli
127.0.0.1:6379> CONFIG SET protected-mode no
OK
127.0.0.1:6379> set aa bb
OK
127.0.0.1:6379> set ee 11
OK
127.0.0.1:6379> quit
[root@localhost src]#

[root@localhost ~]# gdb