Tcl Cheat Sheet

puts "Hello, World!"

# Single line comment

# Multi-line comments require
# multiple hash symbols

# Save as script.tcl
tclsh script.tcl

tclsh
% puts "Interactive mode"
% exit

set name "John"
set age 30
set price 19.99

puts $name
puts "Hello, $name"
puts "Age: $age"

set x 10
set y 20
set sum [expr {$x + $y}]
puts "Sum: $sum"

set temp 100
unset temp

if {[info exists temp]} {
  puts "Variable exists"
}

proc myProc {} {
  global counter
  incr counter
}

set counter 0
myProc
puts $counter  ;# 1

set fruits {apple banana cherry}
set numbers [list 1 2 3 4 5]

set a 10
set b 3
set sum [expr {$a + $b}]
set diff [expr {$a - $b}]
set prod [expr {$a * $b}]
set quot [expr {$a / $b}]

set count 0
incr count      ;# count = 1
incr count 5    ;# count = 6
incr count -2   ;# count = 4

expr {$a == $b}  ;# Equal
expr {$a != $b}  ;# Not equal
expr {$a > $b}   ;# Greater
expr {$a < $b}   ;# Less
expr {$a >= $b}  ;# Greater or equal
expr {$a <= $b}  ;# Less or equal

expr {$a && $b}  ;# AND
expr {$a || $b}  ;# OR
expr {!$a}       ;# NOT

set str1 "hello"
set str2 "world"

if {$str1 eq $str2} {
  puts "Equal"
}

if {$str1 ne $str2} {
  puts "Not equal"
}

if {$age >= 18} {
  puts "Adult"
}

if {$score >= 60} {
  puts "Pass"
} else {
  puts "Fail"
}

if {$grade >= 90} {
  set result "A"
} elseif {$grade >= 80} {
  set result "B"
} elseif {$grade >= 70} {
  set result "C"
} else {
  set result "F"
}

switch $day {
  Monday {
    puts "Start of week"
  }
  Friday {
    puts "End of week"
  }
  default {
    puts "Midweek"
  }
}

switch -glob $filename {
  *.txt {
    puts "Text file"
  }
  *.log {
    puts "Log file"
  }
  default {
    puts "Other file"
  }
}

for {set i 0} {$i < 10} {incr i} {
  puts $i
}

set count 0
while {$count < 5} {
  puts $count
  incr count
}

set fruits {apple banana cherry}
foreach fruit $fruits {
  puts $fruit
}

set names {John Jane Bob}
set ages {30 25 35}

foreach name $names age $ages {
  puts "$name is $age years old"
}

for {set i 0} {$i < 10} {incr i} {
  if {$i == 5} {
    break
  }
  if {$i == 3} {
    continue
  }
  puts $i
}

proc greet {name} {
  puts "Hello, $name"
}

greet "World"

proc add {a b} {
  return [expr {$a + $b}]
}

set result [add 5 3]
puts $result  ;# 8

proc greet {name {greeting "Hello"}} {
  puts "$greeting, $name"
}

greet "John"              ;# Hello, John
greet "Jane" "Hi"         ;# Hi, Jane

proc sum {args} {
  set total 0
  foreach num $args {
    set total [expr {$total + $num}]
  }
  return $total
}

puts [sum 1 2 3 4 5]  ;# 15

proc increment {varname} {
  upvar $varname var
  incr var
}

set count 10
increment count
puts $count  ;# 11

set fruits {apple banana cherry}
set numbers [list 1 2 3 4 5]
set mixed {John 30 "New York"}

set fruits {apple banana cherry}
set len [llength $fruits]  ;# 3

set fruits {apple banana cherry}
set first [lindex $fruits 0]  ;# apple
set last [lindex $fruits end]  ;# cherry

set numbers {1 2 3 4 5}
set subset [lrange $numbers 1 3]  ;# {2 3 4}

set fruits {apple banana}
lappend fruits cherry orange
puts $fruits  ;# {apple banana cherry orange}

set fruits {apple banana cherry}
set index [lsearch $fruits banana]  ;# 1
set found [lsearch $fruits grape]   ;# -1 (not found)

set numbers {5 2 8 1 9}
set sorted [lsort -integer $numbers]
puts $sorted  ;# {1 2 5 8 9}

set fp [open "output.txt" w]
puts $fp "Hello, World!"
close $fp

set fp [open "log.txt" a]
puts $fp "Log entry"
close $fp

set fp [open "input.txt" r]
set content [read $fp]
close $fp
puts $content

set fp [open "data.txt" r]
while {[gets $fp line] >= 0} {
  puts "Line: $line"
}
close $fp

if {[file exists "test.txt"]} {
  puts "File exists"
}

file copy source.txt dest.txt
file delete temp.txt
file rename old.txt new.txt
file mkdir newdir