为什么egrep无法在AIX上正常工作？

Question

I have a simple egrep for searching C/C++ main files(by searching for the main function):

egrep '^\s*(int|void)\s+main' *.c*

I also have 2 machines one Linux one Aix. On the Linux, this command runs perfectly fine. On the Aix it doesn't - it doesn't return results.Even more, on the Aix the following command does return results:

egrep '^\s*(int|void)\s+' *.c*

What is the reason for this?

Answer 1

The non-GNU egrep supplied in AIX apparently doesn't support the '\\s' escape sequence, at least according to my test.

Try with the following:

egrep '^[ \t]*(int|void)[ \t]+main' *.c*

which seems to work for me for the AIX pgrep.

(but still wondering then how egrep '^\\s*(int|void)\\s+' *.c* could work for you as it doesn't seem to work for me)