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:
>>> import pipes >>> t=pipes.Template() >>> t.append('tr a-z A-Z', '--') >>> f=t.open('/tmp/1', 'w') >>> f.write('hello world') >>> f.close() >>> open('/tmp/1').read() 'HELLO WORLD'
Template objects following methods:
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.)