https://invisible-island.net/mawk/
mawk-code - dumping mawk's byte-code
At startup, mawk compiles the script into byte-code. After that, it
interprets the compiled byte-code. Use the -Wdump option to show the
byte-code.
As mawk executes the program, it maintains a reference to the command
to execute in cdp. After that there may be data and/or references in
cdp[0], cdp[1], etc.
When an operation requires operands, mawk pushes the values (or
array/string references) onto the stack, which updates the stack
pointer sp. When the operation completes, mawk consumes those entries
on the stack, pushing the result (if any) onto the stack.
While executing user-defined functions, mawk maintains a frame pointer
fp to address the function's local variables.
Concatenate array-indices.
Usage:
Forms a multiple array index by concatenating the elements of
sp[1-cnt..0], with each element separated by SUBSEP.
Parameters:
cdp[0]
cnt, the number of elements to concatenate follows the
command.
sp[0]..sp[1-cnt]
hold reference to the elements to concatenate.
Returns the index in sp[0].
Delete an array item.
Usage:
delete array[expr]
Parameters:
sp[0]
points to array
sp[-1]
is an expr
Find the length of an array.
Usage:
length(array)
Parameters:
sp[0]
points to array.
Returns the length of the array in sp[0].
Push array address onto stack.
Usage:
This is used to set up a calling argument for a function.
Parameters:
cdp[0]
array reference follows the command.
Returns the array in sp[0].
Test if an expression is present in an array.
Usage:
(expression in array)
Parameters:
sp[0]
points to an array.
sp[-1]
is an expression.
Returns 1 in sp[0] if the expression is found, 0 otherwise.
Add two numbers.
Usage:
first + second
Parameters:
sp[0]
holds the second value.
sp[-1]
holds the first value.
Returns the sum in sp[0].
Combined addition/assignment.
Usage:
target += source
Parameters:
sp[0]
is the source expression
sp[-1]
points to the target
Stores the sum in the target, leaving sp[0] pointing to the target.
Push reference to array cell, given expression for its index.
Usage:
arrayname[expression]
Parameters:
cdp[0]
an array reference follows the command.
sp[0]
has an expression, used for the index of a cell in the array.
Returns a reference to the addressed cell in sp[0].
Push contents of array cell, given expression for its index.
Usage:
arrayname[expression]
Parameters:
sp[0]
has an expression, used for the index of a cell in the array.
Returns contents of the addressed cell in sp[0].
Update reference to next cell for array loop.
Usage:
for ( i in arrayname ) statement
Parameters:
none
Mawk maintains a stack of array-loop state. It updates the array/cell
references in the current loop's state.
Assigns a value.
Usage:
target = source
Parameters:
sp[0]
is the source expression
sp[-1]
points to the target
Stores the sum in the target, leaving sp[0] pointing to the
target.
Compute arc-tangent of two values.
Usage:
atan2( first, second )
Parameters:
sp[0]
holds the second value
sp[-1]
holds the first value
Returns the result in sp[0].
Call a function.
Usage:
function()
Parameters:
cdp[0]
is a reference to the function block
cdp[1]
holds number of input arguments
Returns function value in sp[0].
Concatenate two strings.
Usage:
first second
Parameters:
sp[0]
is the second string.
sp[-1]
is the first string.
Returns the result in sp[0].
Close the file or pipe associated with an expression.
Usage:
close( expression )
Parameters:
sp[0]
holds the expression identifying the file to close
Returns the status from closing the file, 0 on success or -1 on
failure.
Compute the cosine of a value in radians.
Usage:
cos( value )
Parameters:
sp[0]
is the value.
Returns the result in sp[0].
Delete an array.
Usage:
delete(array)
Parameters:
sp[0]
is the array to delete.
Divide one number by another.
Usage:
first / second
Parameters:
sp[0]
is the second value.
sp[-1]
is the first value.
Returns the quotient in sp[0].
Combined division/assignment.
Usage:
target /= source
Parameters:
sp[0]
is the source
sp[-1]
points to the target
Stores the quotient in the target, leaving sp[0] pointing to the
target.
Compare two values.
Usage:
first == second
Parameters:
sp[0]
is the second value
sp[-1]
is the first value
Returns 1 in sp[0] if the values are equal, otherwise 0.
Exits mawk with a specific exit-code.
Usage:
exit(exit_code)
Parameters:
sp[0]
is the exit_code
Exits mawk with success
Usage:
exit
Parameters:
none
Compute base-e exponential function of a value.
Usage:
exp( value )
Parameters:
sp[0]
is the value
Returns the result in sp[0].
Combination addition/assignment to NF.
Usage:
NF += expression
Parameters:
sp[0]
is the expression to add
Assign an expression to NF.
Usage:
NF = expression
Parameters:
sp[0]
is the expression
Combination division/assignment to NF.
Usage:
NF /= expression
Parameters:
sp[0]
is the expression
Combination modulus/assignment to NF.
Usage:
NF %= expression
Parameters:
sp[0]
is the expression
Combination multiplication/assignment to NF.
Usage:
NF *= expression
Parameters:
sp[0]
is the expression
Post-decrement using NF.
Usage:
NF--
Parameters:
holds a reference to the field to use
Post-increment using NF.
Usage:
NF++
Parameters:
holds a reference to the field to use
Exponentiation using NF.
Usage:
NF ^= expression
Parameters:
sp[0]
is the expression to use
Predecrement using NF.
Usage:
--NF
Parameters:
sp[0]
holds a reference to the field to use
Preincrement using NF.
Usage:
++NF
Parameters:
sp[0]
holds a reference to the field to use
Push array reference to data split-up as fields..
Usage:
$0 = expression
getline
Parameters:
cdp[0]
is a reference to the data to be split/assigned.
Returns the resulting array reference in sp[0].
Push contents of numbered field.
Usage:
$expression
Parameters:
cdp[0]
holds a reference to $expression
cdp[1]
holds expression
Returns the field's value in sp[0].
Combination subtraction/assignment to NF.
Usage:
NF -= expression
Parameters:
sp[0]
holds a reference to the field to use
Push reference to numbered field.
Usage:
$number
Parameters:
sp[0]
holds the field number
Returns a reference to the field in sp[0].
Push content of numbered field.
Usage:
$number
Parameters:
sp[0]
holds the field number
Returns the field's content in sp[0].
Flush the output file or pipe associated with an expression.
Usage:
fflush( expression )
Parameters:
sp[0]
is the expression value
Returns the result in sp[0].
Test if first value is greater than the second.
Usage:
first > second
Parameters:
sp[0]
holds the second value.
sp[-1]
holds the first value.
Returns 1 in sp[0] if the first value is greater than, otherwise 0.
Test if first value is greater than or equal to the second.
Usage:
first >= second
Parameters:
sp[0]
holds the second value.
sp[-1]
holds the first value.
Returns 1 in sp[0] if the first value is greater than or equal,
otherwise 0.
Find the position of the second string in the first.
Usage:
index( first, second )
Parameters:
sp[0]
is the second string
sp[0]
is the first string
Returns the position in sp[0] starting at 1 if found, 0 if not found.
Returns a value truncated towards zero..
Usage:
int( value )
Parameters:
sp[0]
is the value
Returns the result in sp[0].
Go from BEGIN code to MAIN code.
Usage:
(internal state)
Parameters:
none
Jump to a new byte-code position, by a given number of bytes.
Usage:
(internal state)
Parameters:
cdp[0]
holds the (signed) number of bytes by which to jump.
Jump to a new byte-code position if sp[0] is nonzero, by a given number
of bytes.
Usage:
(internal state)
Parameters:
cdp[0]
holds the (signed) number of bytes by which to jump.
sp[0]
holds a value to compare against 0.
Jump to a new byte-code position if sp[0] is zero, by a given number of
bytes.
Usage:
(internal state)
Parameters:
cdp[0]
holds the (signed) number of bytes by which to jump.
sp[0]
holds a value to compare against 0.
Push a local address onto the evaluation stack.
Usage:
(internal state)
Parameters:
cdp[0]
holds the offset from the frame pointer fp.
Returns the address in sp[0].
Push contents of a local variable onto the evaluation stack.
Usage:
(internal state)
Parameters:
cdp[0]
holds the offset from the frame pointer fp.
Returns the contents of the local variable in sp[0].
Pushes a reference to an array onto the evaluation stack.
Usage:
arrayname
Parameters:
cdp[0]
holds the offset from the frame pointer fp of a reference to
an array.
Returns a reference to the array in sp[0].
Pushes a reference to a given array cell onto the evaluation stack.
Usage:
arrayname[expression]
Parameters:
cdp[0]
holds the offset from the frame pointer fp of a reference to
an array.
sp[0]
holds an expression
Returns a reference to the specified array cell in sp[0].
Pushes the contents of a given array cell onto the evaluation stack.
Usage:
arrayname[expression]
Parameters:
cdp[0]
holds the offset from the frame pointer fp of a reference to
an array.
sp[0]
holds an expression
Returns the contents of the specified array cell in sp[0].
Returns the length of a string or array value.
Usage:
length( value )
Parameters:
sp[0]
is the string or array reference
Returns the length in sp[0].
Special jump for logical-OR, always preceded by test.
Usage:
(internal state)
Parameters:
cdp[0]
holds the (signed) number of bytes by which to jump if the
value is nonzero.
sp[0]
holds a value to compare against 0.
Special jump for logical-OR, always preceded by test.
Usage:
(internal state)
Parameters:
cdp[0]
holds the (signed) number of bytes by which to jump if the
value is zero.
sp[0]
holds a value to compare against 0.
Compute the natural logarithm of a value.
Usage:
log( value )
Parameters:
sp[0]
is the value
Returns the result in sp[0].
Test if first value is less than the second.
Usage:
first < second
Parameters:
sp[0]
holds the second value.
sp[-1]
holds the first value.
Returns 1 in sp[0] if the first value is less than, otherwise 0.
Test if first value is less than or equal to the second.
Usage:
first <= second
Parameters:
sp[0]
holds the second value.
sp[-1]
holds the first value.
Returns 1 in sp[0] if the first value is less than or equal, otherwise
0.
Test if $0 matches a given regular expression.
Usage:
$0 ~ regex
Parameters:
cdp[0]
holds a reference to a regular expression.
Returns 1 in sp[0] if $0 matches the regular expression, 0 otherwise.
Test if a given expression matches a given regular expression.
Usage:
expression ~ regex
Parameters:
cdp[0]
holds a reference to a regular expression.
sp[0]
holds an expression to test.
Returns 1 in sp[0] if the expression matches the regular expression, 0
otherwise.
Test if an expression in sp[-1] matches the regular expression in
sp[0].
Usage:
expression ~ regex
Parameters:
sp[0]
holds a reference to a regular expression.
sp[-1]
holds an expression to test.
Returns 1 in sp[0] if the expression matches the regular expression, 0
otherwise.
Converts a date specification in systime format to a timestamp.
Usage:
mktime( string )
Parameters:
sp[0]
holds the date-specification string
Returns the result in sp[0].
Compute modulus/remainder with two operands.
Usage:
first % second
Parameters:
sp[0]
holds the second operand
sp[-1]
holds the first operand
Returns the remainder in sp[0].
Assign modulus/remainder with two operands.
Usage:
first %= second
Parameters:
sp[0]
holds the second operand
cdp[0]
holds the first operand
Returns the remainder in sp[0] as well as replacing the first value.
Compute product with two operands.
Usage:
first * second
Parameters:
sp[0]
holds the second value
sp[-1]
holds the first value
Returns the product in sp[0].
Assign product with two operands.
Usage:
first *= second
Parameters:
sp[0]
holds the second value
sp[-1]
holds the first value
Returns the product in sp[0] as well as replacing the first value.
Compare two values.
Usage:
first != second
Parameters:
sp[0]
is the second value
sp[-1]
is the first value
Returns 1 in sp[0] if the values are not equal, otherwise 0.
Read the next record, restart pattern testing.
Usage:
next
Parameters:
none
Begin processing the next file listed on the command line.
Usage:
nextfile
Parameters:
none
Push the number of fields (NF) onto the evaluation stack.
Usage:
(internal state)
Parameters:
none
Compute a logical negation.
Usage:
! value
Parameters:
sp[0]
holds a value to negate.
Returns the result on the evaluation stack, i.e., 0 if the value is
nonzero and 1 otherwise.
Read into $0 using getline.
Usage:
getline
Parameters:
none
Read into $0 using getline, updating NR and FNR.
Usage:
getline < file
Parameters:
none
Start executing the main section of the script (between BEGIN and END).
Usage:
(internal state)
Parameters:
none
Pop the evaluation stack, discarding the value.
Usage:
(internal state)
Parameters:
none
Finish an array "in" loop, deallocating the state information.
Usage:
(internal state)
Parameters:
none
Post-decrement a value.
Usage:
value --
Parameters:
sp[0]
holds the value to decrement
Returns the updated value in sp[0].
Post-increment a value.
Usage:
value ++
Parameters:
sp[0]
holds the value to increment
Returns the updated value in sp[0].
Compute the first value raised to the power of the second value.
Usage:
first ^ second
Parameters:
sp[0]
holds the second value
sp[-1]
holds the first value
Returns the result in sp[0].
Assign the first value raised to the power of the second value.
Usage:
variable = first ^ second
Parameters:
cdp[0]
is a reference to the variable which will be assigned the
result
sp[0]
holds the second value
sp[-1]
holds the first value
Pre-decrement a value.
Usage:
-- value
Parameters:
sp[0]
holds the value to decrement.
Returns the updated value in sp[0];.
Pre-increment a value.
Usage:
++ value
Parameters:
sp[0]
holds the value to decrement.
Returns the updated value in sp[0];.
Push array address onto stack.
Usage:
(internal state)
Parameters:
cdp[0]
array reference follows the command.
Returns the array in sp[0].
Push a data cell onto the evaluation stack.
Usage:
(internal state)
Parameters:
cdp[0]
is a reference to the data to push
Returns a reference to the result in sp[0].
Push a double floating value onto the evaluation stack.
Usage:
(internal state)
Parameters:
cdp[0]
is a reference to the data to push
Returns a reference to the result in sp[0].
Push contents of next referenced variable onto the evaluation stack.
Usage:
(internal state)
Parameters:
cdp[0]
is a reference to the data cell to copy.
Returns a reference to the result in sp[0].
Reserve the next slot on the evaluation stack, setting its type.
Usage:
(internal state)
Parameters:
cdp[0]
holds the type to set in the new slot, e.g., for data via I/O
redirection
Returns a reference to the result in sp[0].
Push a reference to a string value onto the evaluation stack.
Usage:
(internal state)
Parameters:
cdp[0]
holds a reference to the string value
Returns a reference to the result in sp[0].
Returns a random number between zero and one..
Usage:
rand()
Parameters:
none
Returns the result in sp[0].
Test a range pattern: pat1, pat2 { action }.
Usage:
(internal state)
Parameters:
cdp[0].op
a flag, test pat1 if on else pat2
cdp[1].op
offset of pat2 code from cdp
cdp[2].op
offset of action code from cdp
cdp[3].op
offset of code after the action from cdp
cdp[4]
start of pat1 code
sp[0]
holds arguments for the action.
Return a function value.
Usage:
return value
Parameters:
sp[0]
holds the return value
When calling a function, mawk saves the current stack, creating a new
one. On return, mawk restores the previous stack and returns the
function value in sp[0].
Return from a function without providing a return-value.
Usage:
return
Parameters:
sp[0]
is modified to make the value uninitialized.
As in the ret operation, mawk restores the previous stack. After the
return, sp[0] is an uninitialized value.
Begin an array "in" loop.
Usage:
for ( iterator in arrayname ) statement
Parameters:
sp[0]
holds a reference to the array
sp[-1]
holds a reference to the iteration variable
Mawk pushes a new entry onto the array loop stack, and updates cdp to
point to the statement to execute.
Compute the sine of a value in radians.
Usage:
sin( value )
Parameters:
sp[0]
holds the value
Returns the result in sp[0].
Returns a string constructed from expression-list according to format.
Usage:
sprintf( format [, value1 [,... ] ] )
Parameters:
sp[0]
is the last parameter value; there can be up to 255.
Returns the resulting string in sp[0].
Returns the square root of a value.
Usage:
sqrt( value 0
Parameters:
sp[0]
is the value
Returns the result in sp[0].
Seeds the random number generator.
Usage:
srand( value )
srand( )
Parameters:
sp[0]
is the seed value, which may be uninitialized
Returns the previous seed value in sp[0].
Finish a range pattern.
Usage:
(internal state)
Parameters:
none
Formats the given timestamp using the given format.
Usage:
strftime( format , timestamp , utc )
strftime( format , timestamp )
strftime( format )
strftime( )
Parameters:
Zero to three parameters may be on the stack. If all three are
used, they are as follows:
sp[0]
is the utc flag
sp[-1]
is the timestamp value
sp[-2]
is the format
Returns the result in sp[0].
Subtract the second value from the first.
Usage:
first - second
Parameters:
sp[0]
holds the second value
sp[-1]
holds the first value
Returns the result in sp[0].
Assign the difference of two values to a variable.
Usage:
target = first - second
Parameters:
cdp[0]
holds a reference to the variable to which to assign the
result
sp[0]
holds the second value
sp[-1]
holds the first value
Stores the difference in the target, leaving sp[0] pointing to the
target.
eturns the substring of string s, starting at index i, of length n.
Usage:
substr(s,i,n)
substr(s,i)
Parameters:
Two or three parameters may be on the stack. If all three are
used, they are as follows:
sp[0]
holds the length n.
sp[0]
holds the index i.
sp[0]
holds the string s.
Executes a command, returning the wait-status.
Usage:
status = system( command )
Parameters:
sp[0]
is the command to execute
Returns the wait-status in sp[0].
Returns the current time of day as the number of seconds since the
Epoch.
Usage:
systime( )
Parameters:
none
Returns the result in sp[0].
Test a logical expression.
Usage:
value
Parameters:
sp[0]
holds a value to test.
Returns the result on the evaluation stack, i.e., 1 if the value is
nonzero and 0 otherwise.
Copy a string, converting to lowercase.
Usage:
tolower( value )
Parameters:
sp[0]
is the value to convert
Returns the result in sp[0].
Copy a string, converting to uppercase.
Usage:
toupper( value )
Parameters:
sp[0]
is the value to convert
Returns the result in sp[0].
Unitary minus.
Usage:
- value
Parameters:
sp[0]
contains a value to negate. As a side-effect, if the value
is a string, it is cast to double floating point.
Returns the result in sp[0].
Unitary plus.
Usage:
+ value
Parameters:
sp[0]
contains a value to use. As a side-effect, if the value is a
string, it is cast to double floating point.
Returns the result in sp[0].
mandatory jump
optional (undesirable) jump
optional (desirable) jump
pop pos'n, optional jump if advanced
end of match
arbitrary character (.)
character class
end of string ($)
push position onto stack
start of string (^)
matching a literal string
arbitrary string (.*) Version 1.3.4 2020-08-21 MAWK-CODE(7)