Scripting

Scripting language manual

This manual provides an introduction to RouterOS's built-in powerful scripting language.

Scripting host provides a way to automate some router maintenance tasks by means of executing user-defined scripts bounded to some event occurrence.

Scripts can be stored in the Script repository or can be written directly to the console. The events used to trigger script execution include, but are not limited to the System Scheduler, the Traffic Monitoring Tool, and the Netwatch Tool generated events.

If you are already familiar with scripting in RouterOS, you might want to see our Tips & Tricks.

Line structure

RouterOS script is divided into a number of command lines. Command lines are executed one by one until the end of the script or until a runtime error occurs.

Command-line

RouterOS console uses the following command syntax:

[prefix] [path] command [uparam] [param=[value]] .. [param=[value]]

• [prefix] - ":" or "/" character which indicates if command is ICE or path. It may not be required.
• [path] - relative path to the desired menu level. It may not be required.
• command - one of the commands available at the specified menu level.
• [uparam] - unnamed parameter, must be specified if the command requires it.
• [params] - a sequence of named parameters followed by respective values

The end of the command line is represented by the token “;” or NEWLINE. Sometimes “;” or NEWLINE is not required to end the command line.

Single command inside (), [] or {} does not require any end of command character. The end of the command is determined by the content of the whole script

:if ( true ) do={ :put "lala" }

Each command line inside another command line starts and ends with square brackets "[ ]" (command concatenation).

:put [/ip route get [find gateway=1.1.1.1]]; 

Notice that the code above contains three command lines:

• :put
• /ip route get
• find gateway=1.1.1.1

Command-line can be constructed from more than one physical line by following line joining rules.

Physical Line

A physical line is a sequence of characters terminated by an end-of-line (EOL) sequence. Any of the standard platform line termination sequences can be used:

• Unix – ASCII LF;
• Windows – ASCII CR LF;
• mac – ASCII CR;

Standard C conventions for newline characters can be used ( the \n character).

Comments

The following rules apply to a comment:

• A comment starts with a hash character (#) and ends at the end of the physical line.
• RouterOS does not support multiline comments.
• If (#) character appears inside the string it is not considered a comment.

Example

# this is a comment 
# next line comment
:global a; # another valid comment

:global myStr "part of the string # is not a comment"

Line joining

Two or more physical lines may be joined into logical lines using the backslash character (\).

The following rules apply to use backslash as a line joining tool:

• A line ending in a backslash cannot carry a comment.
• A backslash does not continue a comment.
• A backslash does not continue a token except for string literals.
• A backslash is illegal elsewhere on a line outside a string literal.

Example

:if ($a = true \
	and $b=false) do={ :put “$a $b”; } 
:if ($a = true \ # bad comment 
	and $b=false) do={ :put “$a $b”; }
# comment \
	continued – invalid (syntax error)

Whitespace between tokens

Whitespace can be used to separate tokens. Whitespace is necessary between two tokens only if their concatenation could be interpreted as a different token. Example:

{  
	:local a true; :local b false;
# whitespace is not required 
	:put (a&&b); 
# whitespace is required  
	:put (a and b); 
}

Whitespace characters are not allowed

• between '<parameter>='
• between 'from=' 'to=' 'step=' 'in=' 'do=' 'else='

Example:

#incorrect: 
:for i from = 1 to = 2 do = { :put $i } 
#correct syntax: 
:for i from=1 to=2 do={ :put $i } 
:for i from= 1 to= 2 do={ :put $i } 

#incorrect 
/ip route add gateway = 3.3.3.3 
#correct 
/ip route add gateway=3.3.3.3

Scopes

Variables can be used only in certain regions of the script called scopes. These regions determine the visibility of the variable. There are two types of scopes - global and local. A variable declared within a block is accessible only within that block and blocks enclosed by it, and only after the point of declaration.

Global scope

Global scope or root scope is the default scope of the script. It is created automatically and can not be turned off.

Local scope

User can define their own groups to block access to certain variables, these scopes are called local scopes. Each local scope is enclosed in curly braces ("{ }").

{  
	:local a 3;
	{  
		:local b 4;  
		:put ($a+$b); 
	} #line below will show variable b in light red color since it is not defined in scope  
	:put ($a+$b); 
}

In the code above variable, b has local scope and will not be accessible after a closing curly brace.

So for example, the defined local variable will not be visible in the next command line and will generate a syntax error

[admin@MikroTik] > :local myVar a;
[admin@MikroTik] > :put $myVar
syntax error (line 1 column 7)

Note that even variable can be defined as global, it will be available only from its scope unless it is not referenced to be visible outside of the scope.

{  
	:local a 3; 
	{  
		:global b 4; 
	}  
	:put ($a+$b); 
}

The code above will output 3, because outside of the scope b is not visible. 

Following code will fix the problem and will output 7:

{  
	:local a 3; 
	{  
		:global b 4; 
	}
	:global b;  
	:put ($a+$b); 
}

Keywords

The following words are keywords and cannot be used as variable and function names:

and       or       in

Delimiters

The following tokens serve as delimiters in the grammar:

()  []  {}  :   ;   $   / 

Data types

RouterOS scripting language has the following data types:

Constant Escape Sequences

Following escape sequences can be used to define certain special characters within a string:

Example

:put "\48\45\4C\4C\4F\r\nThis\r\nis\r\na\r\ntest";

which will show on display
HELLO
This
is
a
test


Operators

Arithmetic Operators

Usual arithmetic operators are supported in RouterOS scripting language

Note: for the division to work you have to use braces or spaces around the dividend so it is not mistaken as an IP address

Relational Operators

Logical Operators

Bitwise Operators

Bitwise operators are working on number, IP, and IPv6 address data types.

Calculate subnet address from given IP and CIDR Netmask using "&" operator:

{ 
:local IP 192.168.88.77; 
:local CIDRnetmask 255.255.255.0; 
:put ($IP&$CIDRnetmask); 
}

Get the last 8 bits from the given IP addresses:

 :put (192.168.88.77&0.0.0.255);

Use the "|" operator and inverted CIDR mask to calculate the broadcast address:

{ 
:local IP 192.168.88.77; 
:local Network 192.168.88.0; 
:local CIDRnetmask 255.255.255.0; 
:local InvertedCIDR (~$CIDRnetmask); 
:put ($Network|$InvertedCIDR) 
}

Concatenation Operators

It is possible to add variable values to strings without a concatenation operator:

:global myVar "world"; 

:put ("Hello " . $myVar); 
# next line does the same as above 
:put "Hello $myVar";

By using $[] and $() in the string it is possible to add expressions inside strings:

:local a 5; 
:local b 6; 
:put " 5x6 = $($a * $b)"; 

:put " We have $[ :len [/ip route find] ] routes";

Other Operators

</tr>

[admin@x86] >:global aaa {a=1;b=2}
[admin@x86] > :put ($aaa->"a")
1
[admin@x86] > :put ($aaa->"b")
2

Variables

The scripting language has two types of variables:

• global - accessible from all scripts created by the current user, defined by global keyword;
• local - accessible only within the current scope, defined by local keyword.

Note: Starting from v6.2 there can be undefined variables. When a variable is undefined, the parser will try to look for variables set, for example, by DHCP lease-script or Hotspot on-login

Every variable, except for built-in RouterOS variables, must be declared before usage by local or global keywords. Undefined variables will be marked as undefined and will result in a compilation error. Example:

# following code will result in compilation error, because myVar is used without declaration 
:set myVar "my value"; 
:put $myVar

Correct code:

:local myVar; 
:set myVar "my value"; 
:put $myVar;

The exception is when using variables set, for example, by DHCP lease-script

/system script 
add name=myLeaseScript policy=\ 
	ftp,reboot,read,write,policy,test,winbox,password,sniff,sensitive,api \ 
	source=":log info \$leaseActIP\r\ 
	\n:log info \$leaseActMAC\r\ 
	\n:log info \$leaseServerName\r\ 
	\n:log info \$leaseBound" 

/ip dhcp-server set myServer lease-script=myLeaseScript

Valid characters in variable names are letters and digits. If the variable name contains any other character, then the variable name should be put in double quotes. Example:

#valid variable name 
:local myVar; 
#invalid variable name 
:local my-var; 
#valid because double quoted 
:global "my-var";

If a variable is initially defined without value then the variable data type is set to nil, otherwise, a data type is determined automatically by the scripting engine. Sometimes conversion from one data type to another is required. It can be achieved using data conversion commands. Example:

#convert string to array 
:local myStr "1,2,3,4,5"; 
:put [:typeof $myStr]; 
:local myArr [:toarray $myStr]; 
:put [:typeof $myArr]

Variable names are case-sensitive.

:local myVar "hello" 
# following line will generate error, because variable myVAr is not defined 
:put $myVAr 
# correct code 
:put $myVar

Set command without value will un-define the variable (remove from environment, new in v6.2)

#remove variable from environment 
:global myVar "myValue" 
:set myVar;

Use quotes on the full variable name when the name of the variable contains operators. Example:

:local “my-Var”;
:set “my-Var” "my value";
:put $”my-Var”;

Reserved variable names

All built-in RouterOS properties are reserved variables. Variables that will be defined the same as the RouterOS built-in properties can cause errors. To avoid such errors, use custom designations.

For example, the following script will not work:

{ 
:local type "ether1"; 
/interface print where name=$type; 
}

But will work with different defined variables:

 { 
:local customname "ether1"; 
/interface print where name=$customname; 
}

Commands

Global commands

Every global command should start with the ":" token, otherwise it will be treated as a variable.

[admin@MikroTik] > :put [:timestamp]
2735w21:41:43.481891543

{
:local j [:execute {/interface print follow where [:log info ~Sname~]}];
:delay 10s;
:do { /system script job remove $j } on-error={}
}

[admin@MikroTik] > :retry command={abc} delay=1 max=2 on-error={:put "got error"}
got error

Menu specific commands

Common commands

The following commands are available from most sub-menus:

import

The import command is available from the root menu and is used to import configuration from files created by an export command or written manually by hand.

print parameters

Several parameters are available for print command:

More than one parameter can be specified at a time, for example, /ip route print count-only interval=1 where interface="ether1"

Loops and conditional statements

Loops

Conditional statement

Example:

{  
	:local myBool true;  
	:if ($myBool = false) do={ :put "value is false" } else={ :put "value is true" } 
}

Functions

Scripting language does not allow to create functions directly, however, you could use: parse command as a workaround.

Starting from v6.2 new syntax is added to easier define such functions and even pass parameters. It is also possible to return function value with :return command.

See examples below:

#define function and run it
:global myFunc do={:put "hello from function"}
$myFunc

output:
hello from function

#pass arguments to the function
:global myFunc do={:put "arg a=$a"; :put "arg '1'=$1"} 
$myFunc a="this is arg a value" "this is arg1 value"

output:
arg a=this is arg a value
arg '1'=this is arg1 value

Notice that there are two ways how to pass arguments:

• pass arg with a specific name ("a" in our example)
• pass value without arg name, in such case arg "1", "2" .. "n" is used.

Return example

:global myFunc do={ :return ($a + $b)} 
:put [$myFunc a=6 b=2] 

output: 
8

You can even clone an existing script from the script environment and use it as a function.

#add script
/system script add name=myScript source=":put \"Hello $myVar !\""

:global myFunc [:parse [/system script get myScript source]]
$myFunc myVar=world

output:
Hello world !

For example:

:global my2 "123" 

:global myFunc do={ :global my2; :put $my2; :set my2 "lala"; :put $my2 } 
$myFunc my2=1234 
:put "global value $my2"

The output will be:

1234
lala
global value 123

Nested function example

Note: to call another function its name needs to be declared (the same as for variables)

:global funcA do={ :return 5 } 
:global funcB do={  
	:global funcA;  
	:return ([$funcA] + 4) 
} 
:put [$funcB] 

Output: 
9

Catch run-time errors

Starting from v6.2 scripting has the ability to catch run-time errors.

For example, the [code]:reslove[/code] command if failed will throw an error and break the script.

[admin@MikroTik] > { :put [:resolve www.example.com]; :put "lala";}
failure: dns name does not exist

Now we want to catch this error and proceed with our script:

:do {  
	:put [:resolve www.example.com]; 
} on-error={ :put "resolver failed"}; 
:put "lala" 

output: 

resolver failed 
lala

Operations with Arrays

Warning: Key name in the array contains any character other than lowercase character, it should be put in quotes

For example:

[admin@ce0] > {:local a { "aX"=1 ; ay=2 }; :put ($a->"aX")} 
1

Loop through keys and values

"foreach" command can be used to loop through keys and elements:

[admin@ce0] > :foreach k,v in={2; "aX"=1 ; y=2; 5} do={:put ("$k=$v")} 

0=2 
1=5 
aX=1 
y=2

If the "foreach" command is used with one argument, then the element value will be returned:

[admin@ce0] > :foreach k in={2; "aX"=1 ; y=2; 5} do={:put ("$k")} 

2 
5 
1 
2

Note: If the array element has a key then these elements are sorted in alphabetical order, elements without keys are moved before elements with keys and their order is not changed (see example above).

Change the value of a single array element

[admin@MikroTik] > :global a {x=1; y=2}
[admin@MikroTik] > :set ($a->"x") 5 
[admin@MikroTik] > :environment print 
a={x=5; y=2}

Script repository

Sub-menu level: /system script

Contains all user-created scripts. Scripts can be executed in several different ways:

• on event - scripts are executed automatically on some facility events ( scheduler, netwatch, VRRP)
• by another script - running script within the script is allowed
• manually - from console executing a run command or in winbox

Note: Only scripts (including schedulers, netwatch, etc) with equal or higher permission rights can execute other scripts.

Read-only status properties:

Menu specific commands

Environment

Sub-menu level:

• /system script environment
• /environment

Contains all user-defined variables and their assigned values.

[admin@MikroTik] > :global example;
[admin@MikroTik] > :set example 123
[admin@MikroTik] > /environment print  
"example"=123

Read-only status properties:

Job

Sub-menu level: /system script job

Contains a list of all currently running scripts.
Read-only status properties:

See also

• Scripting Examples
• User-submitted Scripts
• Manual: Scripting Tips and Tricks