Notas de Tcl:

* Everything is a string.

* set name Neftali
  set frase "Hola soy Neftali"
  set p "My pid is [pid]"

* puts "Hello world"
  puts "The value of name is $name"

* [expr 1+1]
  incr i 1
  incr i -2

* while {expression} {
  ...
  } 

* for {start} {expression} {next} {
  ...
  }

* if {condition1} {
  ...
  } elseif {condition2} {
  ...
  } else {
  ...
  }
  
* switch -- $count \
    1 {
     ...
  } 2 {
     ...
  } 3 {
     ...
  }

* Continuation lines:  \  {same line inside}  "same line inside"

* break, continue

* proc fib {pen ult n} {
  ...return... 
  }
  puts [fib pen ult n]

* pass by value
  pass by reference
  global pi,e

* source    to include external files.

* expr   sirve para evaluar expresiones true(1) false(0).
  (0x0-->hexadecimal, 0-->octal)
  expr {$count > 0}
  if {"0x0"=="0"} {puts equal}

* llength
  lindex 
  lrange
  
* foreach element $list {
     puts $element
  } 

* varying argument lists
  proc p1 {a b args}   args is set to a list

* lists of lists
  set {a b {c d} {e {f g {xyz}}}}

* Creating list
  list
  concat
  lappend 
  linsert $list 0 new
  lreplace $list 1 3 x y
  lsearch -exact {a b c d ?} "?"
  lsort $list
  split $line ":"
  join $line "/"

* set format "%1c%_8s==%f" ...
  scan $x "%c%8s%*\[=]%f" ...

* string compare $a $b
  string match "*.c" "main.c"
  string first "uu" "uunet.uu.net"
  string last "uu" "uunet.uu.net"
  string length "foo"
  string index "abcde" 2
  string range "abcde" 2 3
  string tolower "Next"
  string toupper "Next"
  string trimleft $num "-"
  string trimright $num "-"
  string trim $num "-"

* append

* Arrays: uid(i), uid(user,shell)

* info exist variable_name
  info locals variable_name
  info globals variable_name
  info vars variable_name
  info commands 
  info procs 
  info script
  array size
  array names

* unset a
  unset array

* trace

* if [catch divalot] {
    puts "got an error in divalot!"
    exit
  }

* catch
  set errorInfo

* error

* eval $cmd

* upvar (passing by reference)

* Ficheros externos

  open "/etc/passwd" "r" ("w","a")
  
  set input [open "/etc/passwd" "r"]  (stdout,stdin,sterr)
  close $input                        (flush $file)

  while 1 {
     if {[gets $file line]==-1} break
        #do something with $line
  }

Ej1_mio:  #!/usr/bin/tclsh
          set file1 [open "fuerzas" "r"]   
          set file2 [open "salida" "w"]  
          while 1 {
            if {[gets $file1 line]==-1} break
            puts $file2 [split $line ":"]
          }


Ej2_mio:  #!/usr/bin/tclsh
          set file [open "fuerzas" "r"]
          foreach line [split [read $file] "\n"] {
             split $line ":"
          }

* foreach filename [glob *.f] {
     set file [open $filename]
     #do something with file
     close $file
  }     

* file dirname
       tail
       extension
       rootname
       exist 
       size

* exec