1tclsh(1) Tcl Applications tclsh(1)
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8 tclsh - Simple shell containing Tcl interpreter
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11 tclsh ?-encoding name? ?fileName arg arg ...?
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15 Tclsh is a shell-like application that reads Tcl commands from its
16 standard input or from a file and evaluates them. If invoked with no
17 arguments then it runs interactively, reading Tcl commands from stan‐
18 dard input and printing command results and error messages to standard
19 output. It runs until the exit command is invoked or until it reaches
20 end-of-file on its standard input. If there exists a file .tclshrc (or
21 tclshrc.tcl on the Windows platforms) in the home directory of the
22 user, interactive tclsh evaluates the file as a Tcl script just before
23 reading the first command from standard input.
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26 If tclsh is invoked with arguments then the first few arguments specify
27 the name of a script file, and, optionally, the encoding of the text
28 data stored in that script file. Any additional arguments are made
29 available to the script as variables (see below). Instead of reading
30 commands from standard input tclsh will read Tcl commands from the
31 named file; tclsh will exit when it reaches the end of the file. The
32 end of the file may be marked either by the physical end of the medium,
33 or by the character, “\032” (“\u001a”, control-Z). If this character
34 is present in the file, the tclsh application will read text up to but
35 not including the character. An application that requires this charac‐
36 ter in the file may safely encode it as “\032”, “\x1A”, or “\u001a”; or
37 may generate it by use of commands such as format or binary. There is
38 no automatic evaluation of .tclshrc when the name of a script file is
39 presented on the tclsh command line, but the script file can always
40 source it if desired.
41 If you create a Tcl script in a file whose first line is
43 #!/usr/local/bin/tclsh
45 then you can invoke the script file directly from your shell if you
47 mark the file as executable. This assumes that tclsh has been in‐
48 stalled in the default location in /usr/local/bin; if it is installed
49 somewhere else then you will have to modify the above line to match.
50 Many UNIX systems do not allow the #! line to exceed about 30 charac‐
51 ters in length, so be sure that the tclsh executable can be accessed
52 with a short file name.
53 An even better approach is to start your script files with the follow‐
55 ing three lines:
56 #!/bin/sh
58 # the next line restarts using tclsh \
59 exec tclsh "$0" ${1+"$@"}
60 This approach has three advantages over the approach in the previous
62 paragraph. First, the location of the tclsh binary does not have to be
63 hard-wired into the script: it can be anywhere in your shell search
64 path. Second, it gets around the 30-character file name limit in the
65 previous approach. Third, this approach will work even if tclsh is it‐
66 self a shell script (this is done on some systems in order to handle
67 multiple architectures or operating systems: the tclsh script selects
68 one of several binaries to run). The three lines cause both sh and
69 tclsh to process the script, but the exec is only executed by sh. sh
70 processes the script first; it treats the second line as a comment and
71 executes the third line. The exec statement cause the shell to stop
72 processing and instead to start up tclsh to reprocess the entire
73 script. When tclsh starts up, it treats all three lines as comments,
74 since the backslash at the end of the second line causes the third line
75 to be treated as part of the comment on the second line.
76 You should note that it is also common practice to install tclsh with
78 its version number as part of the name. This has the advantage of al‐
79 lowing multiple versions of Tcl to exist on the same system at once,
80 but also the disadvantage of making it harder to write scripts that
81 start up uniformly across different versions of Tcl.
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84 Tclsh sets the following global Tcl variables in addition to those cre‐
85 ated by the Tcl library itself (such as env, which maps environment
86 variables such as PATH into Tcl):
87 argc Contains a count of the number of arg arguments (0 if
89 none), not including the name of the script file.
90 argv Contains a Tcl list whose elements are the arg argu‐
92 ments, in order, or an empty string if there are no arg
93 arguments.
94 argv0 Contains fileName if it was specified. Otherwise, con‐
96 tains the name by which tclsh was invoked.
97 tcl_interactive
99 Contains 1 if tclsh is running interactively (no file‐
100 Name was specified and standard input is a terminal-like
101 device), 0 otherwise.
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104 When tclsh is invoked interactively it normally prompts for each com‐
105 mand with “% ”. You can change the prompt by setting the global vari‐
106 ables tcl_prompt1 and tcl_prompt2. If variable tcl_prompt1 exists then
107 it must consist of a Tcl script to output a prompt; instead of out‐
108 putting a prompt tclsh will evaluate the script in tcl_prompt1. The
109 variable tcl_prompt2 is used in a similar way when a newline is typed
110 but the current command is not yet complete; if tcl_prompt2 is not set
111 then no prompt is output for incomplete commands.
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114 See Tcl_StandardChannels for more explanations.
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117 auto_path(n), encoding(n), env(n), fconfigure(n)
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120 application, argument, interpreter, prompt, script file, shell
121Tcl tclsh(1)