pty --- 偽終端工具¶

原始碼：Lib/pty.py

Thepty module defines operations for handling the pseudo-terminalconcept: starting another process and being able to write to and read from itscontrolling terminal programmatically.

Pseudo-terminal handling is highly platform dependent. This code is mainlytested on Linux, FreeBSD, and macOS (it is supposed to work on other POSIXplatforms but it's not been thoroughly tested).

Thepty module defines the following functions:

pty.fork()¶

Fork. Connect the child's controlling terminal to a pseudo-terminal. Returnvalue is(pid,fd). Note that the child getspid 0, and thefd isinvalid. The parent's return value is thepid of the child, andfd is afile descriptor connected to the child's controlling terminal (and also to thechild's standard input and output).

警告

On macOS the use of this function is unsafe when mixed with usinghigher-level system APIs, and that includes usingurllib.request.

pty.openpty()¶

Open a new pseudo-terminal pair, usingos.openpty() if possible, oremulation code for generic Unix systems. Return a pair of file descriptors(master,slave), for the master and the slave end, respectively.

pty.spawn(argv[,master_read[,stdin_read]])¶

Spawn a process, and connect its controlling terminal with the currentprocess's standard io. This is often used to baffle programs which insist onreading from the controlling terminal. It is expected that the processspawned behind the pty will eventually terminate, and when it doesspawnwill return.

A loop copies STDIN of the current process to the child and data receivedfrom the child to STDOUT of the current process. It is not signaled to thechild if STDIN of the current process closes down.

The functionsmaster_read andstdin_read are passed a file descriptorwhich they should read from, and they should always return a byte string. Inorder to force spawn to return before the child process exits anempty byte array should be returned to signal end of file.

The default implementation for both functions will read and return up to 1024bytes each time the function is called. Themaster_read callback is passedthe pseudoterminal’s master file descriptor to read output from the childprocess, andstdin_read is passed file descriptor 0, to read from theparent process's standard input.

Returning an empty byte string from either callback is interpreted as anend-of-file (EOF) condition, and that callback will not be called afterthat. Ifstdin_read signals EOF the controlling terminal can no longercommunicate with the parent process OR the child process. Unless the childprocess will quit without any input,spawn will then loop forever. Ifmaster_read signals EOF the same behavior results (on linux at least).

Return the exit status value fromos.waitpid() on the child process.

os.waitstatus_to_exitcode() can be used to convert the exit status intoan exit code.

引發一個附帶引數argv 的稽核事件pty.spawn。

在 3.4 版的變更:spawn() now returns the status value fromos.waitpid()on the child process.

importargparseimportosimportptyimportsysimporttimeparser=argparse.ArgumentParser()parser.add_argument('-a',dest='append',action='store_true')parser.add_argument('-p',dest='use_python',action='store_true')parser.add_argument('filename',nargs='?',default='typescript')options=parser.parse_args()shell=sys.executableifoptions.use_pythonelseos.environ.get('SHELL','sh')filename=options.filenamemode='ab'ifoptions.appendelse'wb'withopen(filename,mode)asscript:defread(fd):data=os.read(fd,1024)script.write(data)returndataprint('Script started, file is',filename)script.write(('Script started on%s\n'%time.asctime()).encode())pty.spawn(shell,read)script.write(('Script done on%s\n'%time.asctime()).encode())print('Script done, file is',filename)