Using grep to find function

Question

I need to find the usage of functions like system("rm filename") & system("rm -r filename").

I tried grep -r --include=*.{cc,h} "system" . & grep -r --include=*.{cc,h} "rm" . but they are giving too many outcomes.

How do I search for all the instances of system("rm x") where 'x' can be anything. Kind of new with grep.

I'd add a space to that pattern, aragaer. But calls to rmdir or similar should be rare anyway. — Alfe
– Alfe, Commented Aug 7, 2013 at 10:38
For files, better use the unlink(2) syscall or the remove(3) library function that calling system("rm — Basile Starynkevitch
– Basile Starynkevitch, Commented Aug 7, 2013 at 10:58

rook · Accepted Answer · 2013-08-07 10:53:41Z

1

Try:

grep -E "system\(\"rm [a-zA-Z0-9 ]*\"\)" file.txt

Regexp [a-zA-Z0-9 ] builds a pattern for grep what it needs to find in x of system("rm x"). Unfortunately, grep don't supports groups for matching, so you will need to specify it directly what to search.

answered Aug 7, 2013 at 10:53

rook

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Basile Starynkevitch · Accepted Answer · 2013-08-07 12:45:36Z

A possible way might be to work inside the GCC compiler. You could use the MELT domain specific language for that. It provides easy matching on Gimple internal representation of GCC.

It is more complex than textual solutions, but it would also find e.g. calls to system inside functions after inlining and other optimizations.

^{So customizing the GCC compiler is probably not worth the effort for your case, unless you have a really large code base (e.g. million of lines of source code).}

In a simpler textual based approach, you might pipe two greps, e.g.

   grep -rwn system * | grep -w rm

or perhaps just

   grep -rn 'system.*rm' *

BTW, in some big enough software, you may probably have a lot of code like e.g.

  char cmdbuf[128];
  snprintf (cmdbuf, sizeof(cmdbuf), "rm %s", somefilepath);
  system (cmdbuf);

and in that case a simple textual grep based approach is not enough (unless you inspect visually surrounding code).

Andy Lester · Accepted Answer · 2013-08-07 13:11:26Z

0

Install ack (http://beyondgrep.com) and your call is:

ack --cc '\bsystem\(.+\brm\rb'

answered Aug 7, 2013 at 13:11

Andy Lester

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2 Comments

Nicola Over a year ago

Not sure how using your tool (in this case) is different from grep -P. Also, it seems --cc is not supported (according to the docs)

Andy Lester Over a year ago

Functionally it's not different. It's just less typing and less to get wrong. --cc is a filetype. See ack --help-types.

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