TCL Cheatsheet

1946



Sample program

set name [gets stdin]
puts "Hello $name"
  • set : To set data to a variable
  • gets stdin : to read input data from Console
  • puts : prints data to the console.
  • # : Single line comment

Variables

set name onecompiler

Operators

Operator typeDescription
Arithmetic Operator+ , - , * , / , %
comparision Operator< , > , <= , >=, != , ==
Bitwise Operator& , ^ , |, <<, >>
Logical Operator&& , ||, !
Ternary Operator? :

Conditional Statements

1. If-Else

if(conditional-expression) {
   #code
} else {
   #code
}

2. Switch

switch(conditional-expression) {    
value1 {     
 # code
}    
value1 {     
 # code
}    
...
default {
# code
}

Loops

1. For

for{start}{test}{next}{  
  # code  
}

2. While

while(condition) {  
 # code 
}

Arrays

set ArrayName(Index) value

Lists

set listName { i1 i2 i3 .. in }
# or
set listName [list i1 i2 i3]
# or 
set listName [split "items which separated by a character" split_character]

Dictionary

Dictionary is a collection of key-value pairs.

dict set dictName key value
# or 
dict create dictName key1 value1 key2 value2 .. keyn valuen

Procedures

proc procedureName {arguments} {
   # code
}

File Handling

Opening a file

open fileName Mode
ModeDescription
"r"Read-only(default mode)
"r+"Read-write, File must be present already.
"w"Write-only
"w+"Read-write, creates new file if file doesn't exist
"a"Write-only, appends data at the end of file if file exists else creates a new file
"a+"Read-write, read data from beginning but appends data at the end of file if file exists else creates a new file

Closing a file

close fileName

Writing to a file

puts $filename "data to write to the file"