pipes
— Interface to shell pipelines¶
Código-fonte: Lib/pipes.py
Obsoleto desde a versão 3.11: The pipes
module is deprecated
(see PEP 594 for details).
Please use the subprocess
module instead.
The pipes
module defines a class to abstract the concept of a pipeline
— a sequence of converters from one file to another.
Because the module uses /bin/sh command lines, a POSIX or compatible
shell for os.system()
and os.popen()
is required.
The pipes
module defines the following class:
-
class
pipes.
Template
¶ Uma abstração de um pipeline
Exemplo:
>>> import pipes
>>> t = pipes.Template()
>>> t.append('tr a-z A-Z', '--')
>>> f = t.open('pipefile', 'w')
>>> f.write('hello world')
>>> f.close()
>>> open('pipefile').read()
'HELLO WORLD'
Objetos Template¶
Template objects following methods:
-
Template.
reset
()¶ Restore a pipeline template to its initial state.
-
Template.
clone
()¶ Return a new, equivalent, pipeline template.
-
Template.
debug
(flag)¶ If flag is true, turn debugging on. Otherwise, turn debugging off. When debugging is on, commands to be executed are printed, and the shell is given
set -x
command to be more verbose.
-
Template.
append
(cmd, kind)¶ Append a new action at the end. The cmd variable must be a valid bourne shell command. The kind variable consists of two letters.
The first letter can be either of
'-'
(which means the command reads its standard input),'f'
(which means the commands reads a given file on the command line) or'.'
(which means the commands reads no input, and hence must be first.)Similarly, the second letter can be either of
'-'
(which means the command writes to standard output),'f'
(which means the command writes a file on the command line) or'.'
(which means the command does not write anything, and hence must be last.)
-
Template.
prepend
(cmd, kind)¶ Add a new action at the beginning. See
append()
for explanations of the arguments.
-
Template.
open
(file, mode)¶ Return a file-like object, open to file, but read from or written to by the pipeline. Note that only one of
'r'
,'w'
may be given.
-
Template.
copy
(infile, outfile)¶ Copy infile to outfile through the pipe.