--- name: "mawk-code" section: "7" platform: "linux" package: "mawk" version: "1.3.4.20250131-1" release: "Debian 13 (Trixie)" platforms: ["linux"] url: "https://new.carta.tech/mawk-code" --- # mawk-code(7) dumping mawk's byte-code ## NAME mawk-code - dumping mawk's byte-code ## SYNOPSIS 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. ## PROGRAM CODES 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. ### a\_cat *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\[0\]. ### a\_del *Delete an array item*. Usage: delete array\[expr\] Parameters: - sp\[0\] points to *array* - sp\[-1\] is an *expr* ### a\_length *Find the length of an array*. Usage: length(array) Parameters: - sp\[0\] points to *array*. Returns the length of the array in sp\[0\]. ### a\_pusha *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\[0\]. ### a\_test *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 *Add two numbers*. Usage: *first* + *second* Parameters: - sp\[0\] holds the *second* value. - sp\[-1\] holds the *first* value. Returns the sum in sp\[0\]. ### add\_asg *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*. ### ae\_pusha *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\[0\]. ### ae\_pushi *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\[0\]. ### aloop *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. ### assign *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*. ### atan2 *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 *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\[0\]. ### cat *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 *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. ### cos *Compute the cosine of a value in radians*. Usage: cos( *value* ) Parameters: - sp\[0\] is the *value*. Returns the result in sp\[0\]. ### del\_a *Delete an array*. Usage: delete(array) Parameters: - sp\[0\] is the *array* to delete. ### div *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\[0\]. ### div\_asg *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. ### eq *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. ### exit *Exits mawk with a specific exit-code*. Usage: exit(*exit\_code*) Parameters: - sp\[0\] is the *exit\_code* ### exit0 *Exits mawk with success* Usage: exit Parameters: none ### exp *Compute base-e exponential function of a value*. Usage: exp( *value* ) Parameters: - sp\[0\] is the *value* Returns the result in sp\[0\]. ### f\_add\_asg *Combination addition/assignment to NF*. Usage: NF += *expression* Parameters: - sp\[0\] is the *expression* to add ### f\_assign *Assign an expression to NF*. Usage: NF = *expression* Parameters: - sp\[0\] is the *expression* ### f\_div\_asg *Combination division/assignment to NF*. Usage: NF /= *expression* Parameters: - sp\[0\] is the *expression* ### f\_mod\_asg *Combination modulus/assignment to NF*. Usage: NF %= *expression* Parameters: - sp\[0\] is the *expression* ### f\_mul\_asg *Combination multiplication/assignment to NF*. Usage: NF \*= *expression* Parameters: - sp\[0\] is the *expression* ### f\_post\_dec *Post-decrement using NF*. Usage: NF-- Parameters: holds a reference to the field to use ### f\_post\_inc *Post-increment using NF*. Usage: NF++ Parameters: holds a reference to the field to use ### f\_pow\_asg *Exponentiation using NF*. Usage: NF ^= *expression* Parameters: - sp\[0\] is the expression to use ### f\_pre\_dec *Predecrement using NF*. Usage: \--NF Parameters: - sp\[0\] holds a reference to the field to use ### f\_pre\_inc *Preincrement using NF*. Usage: \++NF Parameters: - sp\[0\] holds a reference to the field to use ### f\_pusha *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\[0\]. ### f\_pushi *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\[0\]. ### f\_sub\_asg *Combination subtraction/assignment to NF*. Usage: NF -= *expression* Parameters: - sp\[0\] holds a reference to the field to use ### fe\_pusha *Push reference to numbered field*. Usage: $*number* Parameters: - sp\[0\] holds the field *number* Returns a reference to the field in sp\[0\]. ### fe\_pushi *Push content of numbered field*. Usage: $*number* Parameters: - sp\[0\] holds the field *number* Returns the field's content in sp\[0\]. ### fflush *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\[0\]. ### gt *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. ### gte *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. ### index *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. ### int *Returns a value truncated towards zero.*. Usage: int( *value* ) Parameters: - sp\[0\] is the value Returns the result in sp\[0\]. ### jmain *Go from BEGIN code to MAIN code*. Usage: (internal state) Parameters: - none ### jmp *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. ### jnz *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. ### jz *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. ### l\_pusha *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\[0\]. ### l\_pushi *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\[0\]. ### la\_pusha *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\[0\]. ### lae\_pusha *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\[0\]. ### lae\_pushi *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\[0\]. ### length *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\[0\]. ### ljnz *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.* ### ljz *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.* ### log *Compute the natural logarithm of a value.* *Usage:* *log( value )* *Parameters:* - *sp\[0\]* *is the value* *Returns the result in sp\[0\].* ### lt *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.* ### lte *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.* ### match0 *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.* ### match1 *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.* ### match2 *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.* ### mktime *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\[0\].* ### mod *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\[0\].* ### mod\_asg *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.* ### mul *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\[0\].* ### mul\_asg *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.* ### neq *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.* ### next *Read the next record, restart pattern testing.* *Usage:* *next* *Parameters:* - *none* ### nextfile *Begin processing the next file listed on the command line.* *Usage:* *nextfile* *Parameters:* - *none* ### nf\_pushi *Push the number of fields (NF) onto the evaluation stack.* *Usage:* *(internal state)* *Parameters:* - *none* ### not *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.* ### ol\_gl *Read into $0 using getline.* *Usage:* *getline* *Parameters:* - *none* ### ol\_gl\_nr *Read into $0 using getline, updating NR and FNR.* *Usage:* *getline \< file* *Parameters:* - *none* ### omain *Start executing the main section of the script (between BEGIN and END).* *Usage:* *(internal state)* *Parameters:* - *none* ### pop *Pop the evaluation stack, discarding the value.* *Usage:* *(internal state)* *Parameters:* - *none* ### pop\_al *Finish an array “in” loop, deallocating the state information.* *Usage:* *(internal state)* *Parameters:* - *none* ### post\_dec *Post-decrement a value.* *Usage:* *value --* *Parameters:* - *sp\[0\]* *holds the value to decrement* *Returns the updated value in sp\[0\].* ### post\_inc *Post-increment a value.* *Usage:* *value ++* *Parameters:* - *sp\[0\]* *holds the value to increment* *Returns the updated value in sp\[0\].* ### pow *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\[0\].* ### pow\_asg *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\_dec *Pre-decrement a value.* *Usage:* *-- value* *Parameters:* - *sp\[0\]* *holds the value to decrement.* *Returns the updated value in sp\[0\];.* ### pre\_inc *Pre-increment a value.* *Usage:* *++ value* *Parameters:* - *sp\[0\]* *holds the value to decrement.* *Returns the updated value in sp\[0\];.* ### pusha *Push array address onto stack.* *Usage:* *(internal state)* *Parameters:* - *cdp\[0\]* *array reference follows the command.* *Returns the array in sp\[0\].* ### pushc *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\[0\].* ### pushd *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\[0\].* ### pushi *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\[0\].* ### pushint *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\[0\].* ### pushs *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\[0\].* ### rand *Returns a random number between zero and one..* *Usage:* *rand()* *Parameters:* - *none* *Returns the result in sp\[0\].* ### range *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.* ### ret *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\[0\].* ### ret0 *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.* ### set\_al *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.* ### sin *Compute the sine of a value in radians.* *Usage:* *sin( value )* *Parameters:* - *sp\[0\]* *holds the value* *Returns the result in sp\[0\].* ### sprintf *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\[0\].* ### sqrt *Returns the square root of a value.* *Usage:* *sqrt( value 0* *Parameters:* - *sp\[0\]* *is the value* *Returns the result in sp\[0\].* ### srand *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\[0\].* ### stop *Finish a range pattern.* *Usage:* *(internal state)* *Parameters:* - *none* ### strftime *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\[0\].* ### sub *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\[0\].* ### sub\_asg *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.* ### substr *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.* ### system *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\[0\].* ### systime *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 *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.* ### tolower *Copy a string, converting to lowercase.* *Usage:* *tolower( value )* *Parameters:* - *sp\[0\]* *is the value to convert* *Returns the result in sp\[0\].* ### toupper *Copy a string, converting to uppercase.* *Usage:* *toupper( value )* *Parameters:* - *sp\[0\]* *is the value to convert* *Returns the result in sp\[0\].* ### uminus *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\[0\].* ### uplus *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\[0\].* ## REGULAR EXPRESSIONS ### M\_1J *mandatory jump* ### M\_2JA *optional (undesirable) jump* ### M\_2JB *optional (desirable) jump* ### M\_2JC *pop position, optional jump (to continue looping) if advanced* ### M\_ACCEPT *end of match* ### M\_ANY *arbitrary character (.)* ### M\_CLASS *character class* ### M\_END *end of string ($)* ### M\_ENTER *prepare an iteration by resetting the counter.* *This precedes a* **M\_SAVE\_POS***.* ### M\_LOOP *Like* **M\_2JC***, this is the last part of a conditional loop.* *It is used where one or both of the minimum and maximum iterations are known.* ### M\_SAVE\_POS *push position onto stack, at the beginning of a loop* ### M\_START *start of string (^)* ### M\_STR *matching a literal string* ### M\_U *arbitrary string (.\*)*