PyAWK

A simple variant of AWK in Python.

1| Motivation

Keep simple, wonderful and the most frequently used features in awk, while replacing the complicated and ambiguous syntax with Python. As a result, we can get the power of both Python and awk by using pyawk, a pythonic awk.

2| pyawk vs awk

• usage

  pyawk:

    pyawk [option] 'pattern { action }' file
  

  awk:

    awk [option] 'pattern { action }' file1 file2 ...
  

• option

  pyawk	awk	Remarks
  -F fs	-F fs
  -f progfile	-f progfile	(1)
  -v (verbose)	-v var=val
  ×	other options in awk

  (1) In pyawk, "progfile" is actually a Python module, in which all commands are included in a list called cmds. While "progfile" is just a normal text file in awk.

• pattern

  pyawk	awk	Remarks
  /regex/ <=> $0/regex/	/regex/ <=> $0 ~ /regex/	(1)
  $1/regex/	$1 ~ /regex/	(1)
  $1!/regex/	$1 !~ /regex/	(1)
  all valid expressions in Python	all valid expressions in awk	(2)
  begpat, endpat	begpat, endpat	(3)
  BEGIN { action }	BEGIN { action }	(4)
  END { action }	END { action }	(4)
  no pattern <=> match every record	no pattern <=> match every record	(5)
  ×	other patterns in awk

  (1) regular expression

  (2) expression

  (3) begpat, endpat

  (4) BEGIN/END

  (5) empty

• action

  pyawk	awk
  all valid statements in Python	all valid statements in awk
  print($1, $2, $3)	print $1, $2, $3
  no action <=> print($0)	no action <=> print $0
  print (×, must be print($0))	print (√, <=> print $0)
  ×	variables used before defined

• built-in variable

  pyawk	awk	Remarks
  NR	NR	Number of Records
  NF	NF	Number of Fields
  FS	FS	input Field Separator
  RS	RS	input Record Separator
  OFS	OFS	Output Field Separator
  ORS	ORS	Output Record Separator
  ×	other built-in variables in awk

3| Usage

1) Install

sudo python setup.py install

2) Uninstall

sudo python setup.py uninstall

3) Examples

See help message of command pyawk:

pyawk 'END { print(NR) }' /etc/passwd
echo -e 'python .py\nperl .pl\nshell .sh' | pyawk '$2!/pl/{ print($1) }'
ps aux | pyawk 'BEGIN { print("USER|PID|COMMAND") }; $2 == 10, $2 == 50 { print($1, $2, $11) }'

See directory sample:

pyawk -f sample.cmds sample/data.txt