chan - Manipulate channels

http://purl.org/tcl/home/man/tcl8.5/TclCmd/chan.htm 

'''chan''' ''option'' ?''arg arg ...''?
** See Also **
This command (introduced in Tcl 8.5) provides several operations on a channel, including many that have been available using a mix of other commands. ''Option'' indicates what to do with the channel. Any unique abbreviation for ''option'' is acceptable. The valid ''option''s are: (see complete man page; here's only notes on selected options).
    :   '''chan''' ''action'' ?''arg arg ...''?
''Why was thing thing called 'chan' instead of 'channel'?'' 
[schlenk]: It's mentioned in the TIP [http://www.tcl.tk/cgi-bin/tct/tip/208.html], basically same style as [interp] for interpreter. 
    [TIP] [http://www.tcl.tk/cgi-bin/tct/tip/208%|%208]:   add `chan`
''I see. Thank
you for pointing that out. Pretty lame reasoning when "channel" is much more descriptive. But I'm not the 
one doing all the work so I'm not complaining! ''

[JYL] If you dont like chan you can do 'interp alias {} channel {} chan'


[AMG]: `chan` aggregates all the commands you'll need for working with
'''[chan blocked]''' ''channelId''

'''[chan close]''' ''channelId''

'''[chan configure]''' ''channelId'' ?''optionName''? ?''value''? ?''optionName value''?...

'''[chan copy]''' ''inputChan outputChan'' ?''options...''?

'''[chan create]''' ''mode cmdPrefix''

'''[chan eof]''' ''channelId''

'''[chan event]''' ''channelId event'' ?''script''?

'''[chan flush]''' ''channelId''

'''[chan gets]''' ''channelId'' ?''varName''?

'''[chan names]''' ?''globPattern''?

'''[chan postevent]''' ''channelId eventSpec''

'''[chan puts]''' ?'''-nonewline'''? ?''channelId''? ''string''

'''[chan read]''' ''channelId'' ?''numChars''?

'''[chan read]''' ?'''-nonewline'''? ''channelId''

'''[chan seek]''' ''channelId offset'' ?''origin''?

'''[chan tell]''' ''channelId''

'''[chan truncate]''' ''channelId'' ?''length''?

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TIP 287 proposes a [['''chan available''' ''channelId'']] command to find out how much available input is currently being buffered that could be [chan read] in. (It would make it safe to use [chan gets] with [socket]s since you could introspect and detect someone sending an excessively long line rather than running out of memory first.)

See also [chan mode] for an example how to extend that [ensemble].
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[RS] History sometimes runs in circles... [Tcl 2.1] didn't have commands dealing with channels. [Peter da Silva] added the "stream" extension, where one could write
  stream fp open $filename r
  set x [stream fp gets]
  stream fp close
Later, the parts of "stream" went into the core as separate commands. Still later (in 8.5), they get reunited again in [chan], which arguably makes the command set leaner, but scripts wordier...
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[[
[Category Command] of [Tcl] 8.5 |
[Category Channel]
]]