Check variables declaration for shell script.

check_sh_variables_declaration.py

#!/usr/bin/env python

# require: python 2.4+
# usage: python sh_declaration_checker.py < sample.sh

from re import findall
from sys import stdin

usedVarlist = set()
declaredVarlist = set()

for line in stdin:
    # skip comment line
    if line.strip()[0:1] == "#":
        continue
    # read declared
    for i in findall("read +[a-zA-Z0-9_]+", line):
        declaredVarlist.add(i[4:].strip())
    # for loop declared
    for i in findall("for +[a-zA-Z0-9_]+", line):
        declaredVarlist.add(i[3:].strip())
    # normal declared
    for i in findall("[a-zA-Z0-9_]+=", line):
        if not i[:-1].isdigit():
            declaredVarlist.add(i[:-1])
    # used
    if "$" in line:
        for i in findall("\${?[a-zA-Z0-9_]+}?", line):
            if not i[1:].strip("{}").isdigit():
                usedVarlist.add(i[1:].strip("{}"))

for i in usedVarlist:
    if i in declaredVarlist:
        print(i + " is declared in this file.")
    else:
        print(i + " is *NOT* declared in this file.")

# vim: set ts=4 sw=4 sts=4 expandtab: #