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README.md

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-erlyssh
-=======
-
-A Parallel SSH Execution Tool
+erlyssh - A Parallel SSH Execution Tool
+=======
+
+Intro:
+--------
+This is an Erlang Powered linux command line tool.You can use this tool to 
+connect to mass of servers through SSH client simultaneously and parallel 
+execute noninteractive shell commands on every connected server. 
+
+Requirements:
+--------
+1. openssh client with agent foward enabled
+2. GNU lib readline(libreadline.so,libhistory.so)
+3. Erlang 5.6/OTP R12B or later
+4. Linux or Mac OSX
+5. autoconf automake libtool required for building
+
+Install:
+--------
+run autoreconf -i to generate configure Makefile.in etc.
+
+run ./configure
+
+run sudo make install
+
+or you can provide --prefix=/custom-install-path/ as ./configure option
+
+if any buid error occurs, try to check
+1. Is libreadline's arch compatible with your erlang runtime
+2. Check include path and library path, add your custom -I -L to CFLAGS env
+3. Is your default system arch compatible with your erlang runtime, otherwise
+add -arch parameter to CFLAGS env
+
+Usage:
+--------
+###configure server list
+export ESSH_LIST_HOME = /your-path-to-put-server-list-files
+
+in ESSH_HOME_DIR put your server list files, Use the following format:
+
+	www-11.internal.org
+	www-15.internal.org
+	172.19.0.86
+	-p1046 172.19.1.87
+	#comment: each server address(domain or ip) a line 
+	#as ssh command's paras`
+
+
+###run shell script
+Start erlyssh with:
+
+	radiumce@app-88:~$ essh cometd                                             
+	-----------------www-11 connected-------------------                    
+	-----------------www-15 connected------------------- 
+
+	essh>: 
+After 'essh>:'  prompt, you can run any non-interactive commands.
+for exmaple:
+
+	radiumce@app-88:~$ essh cometd
+	-----------------www-11 connected-------------------
+	-----------------www-15 connected-------------------
+
+	essh>: ls
+	--------------www-11---------------
+	erlang
+
+
+	[primary server done]
+	->>
+
+	essh>:
+Input a 'ls' command, and it will parallel executed on www-11,www-15.
+In erlyssh the first server on the list will be the primary server. Its output is 
+realtime(it is useful when running some long duration commands, such as 'svn up').
+when the command on www-15 is done, it will compare with the out put of www-11.
+when their output is identical, erlssh just print a '->>' as www-15's output.
+
+
+	essh>: #con 5
+	set concurrent execution limits = 5
+	essh>: 
+Schedule parameter 'con'(limit of parallel connections, default 256) can be set by '#con number'
+
+
+	essh>: #intv 5
+	set execution interval = 5s
+	essh>: 
+Schedule parameter 'intv'(execution interval, default 0) can be set by '#intv ${seconds}'
+
+	essh>: exit;
+	Thanks for using essh, bye.
+Use command 'exit;'(ends with ';') to exit the shell.
+
+Tips:
+--------
+1. erlyssh is interactive(you can use 'cd' to change path) but it can only 
+execute non-interactive commands.
+2. When there is mass of servers, add
+
+	CheckHostIP no
+
+	StrictHostKeyChecking no
+
+   to your .ssh/config can avoid some yes/no security confirm
+3. Many shell commands have their non-interactive mode or corresponded 
+non-interactive commands. Such as 'svn' commands have non-interactive
+mode and 'sed' can help you to perform plain text processing.