1tclsh(1) Tcl Applications tclsh(1)
2______________________________________________________________________________
6
8 tclsh - Simple shell containing Tcl interpreter
9
11 tclsh ?fileName arg arg ...?
12_________________________________________________________________
13
16 Tclsh is a shell-like application that reads Tcl commands from its
17 standard input or from a file and evaluates them. If invoked with no
18 arguments then it runs interactively, reading Tcl commands from stan‐
19 dard input and printing command results and error messages to standard
20 output. It runs until the exit command is invoked or until it reaches
21 end-of-file on its standard input. If there exists a file .tclshrc (or
22 tclshrc.tcl on the Windows platforms) in the home directory of the
23 user, tclsh evaluates the file as a Tcl script just before reading the
24 first command from standard input.
25
28 If tclsh is invoked with arguments then the first argument is the name
29 of a script file and any additional arguments are made available to the
30 script as variables (see below). Instead of reading commands from
31 standard input tclsh will read Tcl commands from the named file; tclsh
32 will exit when it reaches the end of the file. The end of the file may │
33 be marked either by the physical end of the medium, or by the charac‐ │
34 ter, '\032' ('\u001a', control-Z). If this character is present in the │
35 file, the tclsh application will read text up to but not including the │
36 character. An application that requires this character in the file may │
37 safely encode it as ``\032'', ``\x1a'', or ``\u001a''; or may generate │
38 it by use of commands such as format or binary. There is no automatic
39 evaluation of .tclshrc when the name of a script file is presented on
40 the tclsh command line, but the script file can always source it if
41 desired.
42 If you create a Tcl script in a file whose first line is
44 #!/usr/local/bin/tclsh
45 then you can invoke the script file directly from your shell if you
46 mark the file as executable. This assumes that tclsh has been
47 installed in the default location in /usr/local/bin; if it's installed
48 somewhere else then you'll have to modify the above line to match.
49 Many UNIX systems do not allow the #! line to exceed about 30 charac‐
50 ters in length, so be sure that the tclsh executable can be accessed
51 with a short file name.
52 An even better approach is to start your script files with the follow‐
54 ing three lines:
55 #!/bin/sh
56 # the next line restarts using tclsh \
57 exec tclsh "$0" "$@"
58 This approach has three advantages over the approach in the previous
59 paragraph. First, the location of the tclsh binary doesn't have to be
60 hard-wired into the script: it can be anywhere in your shell search
61 path. Second, it gets around the 30-character file name limit in the
62 previous approach. Third, this approach will work even if tclsh is
63 itself a shell script (this is done on some systems in order to handle
64 multiple architectures or operating systems: the tclsh script selects
65 one of several binaries to run). The three lines cause both sh and
66 tclsh to process the script, but the exec is only executed by sh. sh
67 processes the script first; it treats the second line as a comment and
68 executes the third line. The exec statement cause the shell to stop
69 processing and instead to start up tclsh to reprocess the entire
70 script. When tclsh starts up, it treats all three lines as comments,
71 since the backslash at the end of the second line causes the third line
72 to be treated as part of the comment on the second line.
73 You should note that it is also common practise to install tclsh with │
75 its version number as part of the name. This has the advantage of │
76 allowing multiple versions of Tcl to exist on the same system at once, │
77 but also the disadvantage of making it harder to write scripts that │
78 start up uniformly across different versions of Tcl.
79
82 Tclsh sets the following Tcl variables:
83 argc Contains a count of the number of arg arguments (0 if
85 none), not including the name of the script file.
86 argv Contains a Tcl list whose elements are the arg argu‐
88 ments, in order, or an empty string if there are no arg
89 arguments.
90 argv0 Contains fileName if it was specified. Otherwise, con‐
92 tains the name by which tclsh was invoked.
93 tcl_interactive
95 Contains 1 if tclsh is running interactively (no file‐
96 Name was specified and standard input is a terminal-like
97 device), 0 otherwise.
98
101 When tclsh is invoked interactively it normally prompts for each com‐
102 mand with ``% ''. You can change the prompt by setting the variables
103 tcl_prompt1 and tcl_prompt2. If variable tcl_prompt1 exists then it
104 must consist of a Tcl script to output a prompt; instead of outputting
105 a prompt tclsh will evaluate the script in tcl_prompt1. The variable
106 tcl_prompt2 is used in a similar way when a newline is typed but the
107 current command isn't yet complete; if tcl_prompt2 isn't set then no
108 prompt is output for incomplete commands.
109
112 See Tcl_StandardChannels for more explanations.
113
116 fconfigure(n), tclvars(n)
117
120 argument, interpreter, prompt, script file, shell
121Tcl tclsh(1)