pawk 0.1

# PAWK - A Python line processor (like AWK)

PAWK aims to bring the full power of Python to AWK-like line-processing.

## Expression evaluation

PAWK evaluates a Python expression (or statement if –statement is provided) against each line in stdin. The following variables are available in local context:

• line - Current line text, including newline.

• l - Current line text, excluding newline.

• n - The current 1-based line number.

• f - Fields of the line (split by the field separator -F).

• nf - Number of fields in this line.

Additionally, the –import <module>[,<module>,…] flag can be used to import symbols from a set of modules into the evaluation context.

eg. –import os.path will import all symbols from os.path, such as os.path.isfile(), into the context.

## Output

The type of the evaluated expression determines how output is displayed:

• tuple or list: the elements are converted to strings and joined with the output delimiter (-O).

• None or False: nothing is output for that line.

• Any other value is converted to a string.

## Examples

### Line processing

Print the name and size of every file from stdin:

find . -type f | pawk ‘f[0], os.stat(f[0]).st_size’

> Note: this example also shows how pawk automatically imports referenced modules, in this case os.

Print the sum size of all files from stdin:

find . -type f |

pawk

–statement –begin ‘c=0’ –end ‘print c’ ‘c += os.stat(f[0]).st_size’

Short-flag version:

find . -type f | pawk -sB c=0 -E ‘print c’ ‘c += os.stat(f[0]).st_size’

Transform /etc/hosts into a JSON map of host to IP:

cat /etc/hosts | pawk -sB ‘d={}’ -E ‘print json.dumps(d)’

‘if not l.startswith(“#”): d[f[1]] = f[0]’

### Whole-file processing

If statement mode (-s)is enabled and you do not provide a line expression, pawk will accumulate each line, and the entire file’s text will be available in the end statement as t. This is useful for operations on entire files, like the following example of converting a file from markdown to HTML:

cat README.md |

pawk

–statement –end ‘print markdown.markdown(t)’

Short-flag version:

cat README.md | pawk -sE ‘print markdown.markdown(t)’