2 files changed, 36 insertions(+), 0 deletions(-)

M index.md
A tcl.md

@@ 32,6 32,7 @@ the Internet and don't want to get lost.
 - [C and C++](c-and-cpp.md)
 - [Lua](lua.md)
 - [Python](python.md)
+- [Tcl](tcl.md)
 - [TeX](tex.md)
 
 ## Shell

@@ 0,0 1,35 @@
+---
+title: Tcl
+---
+
+# Links
+
+- [Tcl Commands](https://www.tcl.tk/man/tcl8.6/TclCmd/contents.html)
+- [Tcl Style Guide](https://core.tcl-lang.org/tips/doc/trunk/tip/352.md)
+
+# Getting script directory
+
+The script file name can be discovered using the `info script` command. If that
+doesn't work, the `$argv0` variable can be used:
+
+```tcl
+set ScriptPath [info script]
+if {[string length $ScriptPath] == 0} {
+   set ScriptPath $argv0
+}
+```
+
+This conditional is not necessary if we know how the script will be executed,
+which is often the case.
+
+The next thing to do is to normalize the script path, to get the absolute path:
+
+```tcl
+set ScriptPath [file normalize $ScriptPath]
+```
+
+Finally, get the script directory using the `file dirname` subcommand:
+
+```tcl
+set ScriptDir [file dirname $ScriptPath]
+```