Why is there no platform independent way of clearing a terminal?
in [Python]
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From: Daniel Fetchinson on 27 Jul 2010 08:54 Hi folks, If I'm only interested in linux and windows I know I can do ################################ import os import platform if platform.system( ) == 'Linux': clear = 'clear' else: clear = 'cls' os.system( clear ) ################################ or something equivalent using os.name and friends, but was wondering why there is no platform independent way (i.e. the platform dependence is taken care of by the python stdlib) of clearing a terminal. Sure, there are many different terminals and many different operating systems but in many areas python managed to hide all these complexities behind a well defined API. Why was clearing a terminal left out? Cheers, Daniel -- Psss, psss, put it down! - http://www.cafepress.com/putitdown
From: Bruno Desthuilliers on 27 Jul 2010 10:02 Daniel Fetchinson a �crit : > Hi folks, > > If I'm only interested in linux and windows I know I can do > > ################################ > import os > import platform > > if platform.system( ) == 'Linux': > clear = 'clear' > else: > clear = 'cls' > > os.system( clear ) > ################################ > > or something equivalent using os.name and friends, but was wondering > why there is no platform independent way (i.e. the platform dependence > is taken care of by the python stdlib) of clearing a terminal. Sure, > there are many different terminals and many different operating > systems but in many areas python managed to hide all these > complexities behind a well defined API. > > Why was clearing a terminal left out? > What you're talking about is a shell, not a terminal (a terminal is a physical device). And the shell is not necessarily part of the OS itself (there's no shortage of shells for unices / linux systems), so it doesn't belong to the os or platform modules. FWIW, I can't tell for sure since I never used any other shell than bash, but I'm not sure your above code is garanteed to work on each and any possible unix shell.
From: Grant Edwards on 27 Jul 2010 10:32 On 2010-07-27, Bruno Desthuilliers <bruno.42.desthuilliers(a)websiteburo.invalid> wrote: > Daniel Fetchinson a ?crit : >> Hi folks, >> >> If I'm only interested in linux and windows I know I can do >> >> ################################ >> import os >> import platform >> >> if platform.system( ) == 'Linux': >> clear = 'clear' >> else: >> clear = 'cls' >> >> os.system( clear ) >> ################################ >> >> or something equivalent using os.name and friends, but was wondering >> why there is no platform independent way (i.e. the platform dependence >> is taken care of by the python stdlib) of clearing a terminal. Sure, >> there are many different terminals and many different operating >> systems but in many areas python managed to hide all these >> complexities behind a well defined API. >> >> Why was clearing a terminal left out? >> > > What you're talking about is a shell, not a terminal (a terminal is a > physical device). No, what he's talking about is clearing a terminal (or a terminal emulator). They both work the same, the only difference is whether the terminal software is running on dedicated hardware or on general-purpose hardware. > And the shell is not necessarily part of the OS itself > (there's no shortage of shells for unices / linux systems), so it > doesn't belong to the os or platform modules. True, but clearing a terminal or terminal emulator has nothing to do with the shell. It's done using an in-band control/escape sequence that's indepedent of the shell being used. His example accomplishes this using an executable named 'clear' which knows how to use terminfo/termcap (I forget which one) to send the proper escape sequence to the terminal. > FWIW, I can't tell for sure since I never used any other shell than > bash, but I'm not sure your above code is garanteed to work on each > and any possible unix shell. Again, the shell is irrelevent. -- Grant Edwards grant.b.edwards Yow! Zippy's brain cells at are straining to bridge gmail.com synapses ...
From: Bruno Desthuilliers on 27 Jul 2010 10:44 Grant Edwards a �crit : > On 2010-07-27, Bruno Desthuilliers <bruno.42.desthuilliers(a)websiteburo.invalid> wrote: >> Daniel Fetchinson a ?crit : (snip) >>> Why was clearing a terminal left out? >>> >> What you're talking about is a shell, not a terminal (a terminal is a >> physical device). > > No, what he's talking about is clearing a terminal (or a terminal > emulator). They both work the same, the only difference is whether > the terminal software is running on dedicated hardware or on > general-purpose hardware. (snip) I stand corrected.
From: Daniel Fetchinson on 27 Jul 2010 12:58
>>> Hi folks, >>> >>> If I'm only interested in linux and windows I know I can do >>> >>> ################################ >>> import os >>> import platform >>> >>> if platform.system( ) == 'Linux': >>> clear = 'clear' >>> else: >>> clear = 'cls' >>> >>> os.system( clear ) >>> ################################ >>> >>> or something equivalent using os.name and friends, but was wondering >>> why there is no platform independent way (i.e. the platform dependence >>> is taken care of by the python stdlib) of clearing a terminal. Sure, >>> there are many different terminals and many different operating >>> systems but in many areas python managed to hide all these >>> complexities behind a well defined API. >>> >>> Why was clearing a terminal left out? >>> >> >> What you're talking about is a shell, not a terminal (a terminal is a >> physical device). And the shell is not necessarily part of the OS itself > >> (there's no shortage of shells for unices / linux systems), so it >> doesn't belong to the os or platform modules. >> >> FWIW, I can't tell for sure since I never used any other shell than >> bash, but I'm not sure your above code is garanteed to work on each and >> any possible unix shell. > > Sorry, but that is completely wrong - the shell is irrelevant. > > "clear" is just a normal command line program that queries the > termcap/terminfo database (possibly via the curses library) for the > terminal specific sequence of characters that will clear the screen. It > then writes those characters to stdout. The terminal, or (more usually > these days) terminal emulator, then interprets those characters and takes > the appropriate action. > > I'm not sure what the POSIX status of the clear command is, but I'd be > surprised if it wasn't present on a UNIX/Linux system of any vintage. After getting the technicalities out of the way, maybe I should have asked: Is it only me or others would find a platform independent python API to clear the terminal useful? Cheers, Daniel -- Psss, psss, put it down! - http://www.cafepress.com/putitdown |