Description
Overview
The purpose of this assignment is twofold:
1. To reinforce your understanding of file systems, file types, permissions, and recursive directory structures
2. To teach you how the unix utility ”find” works so that you can benefit from using it in your
studies and career
Program
The program is called as:
./find directory [filters]
Required Filters
-d
evaluates to true and enables debugging
-name filename
evaluates to true if the file name is exactly ”filename”. Wildcards are not supported.
-type filetype
evaluates to true if the file is of type ”filetype”. You should support the following file types:
”f” – regular file
”d” – directory
”l” – symbolic link
”b” – block special (for devices)
”c” – character special (for devices)
-size sizespec
If the first character of ”filespec” is a ’-’, it evaluates to true if the file is smaller than the
size specified. If the first character of ”filespec” is a ’+’, it evaluates to true if the file is
larger than the size specified. If the first character of ”filespec” is a digit, it evaluates to
true if the file is exactly the size specified.
If the filespec ends in the character ’c’, then the size is in characters and the size should be
compared against st size in the file’s ”struct stat”. Otherwise the size is in ”blocks” and
should be compared against the file’s st blocks.
Extra Credit Filters
-ls
Always evaluates to true and uses the long output format for all file output. The output
should be identical to the real find command.
-mtime timespec
evaluates to true if the modified time of the file matches timespec (see the ”find” manual
page).
-mmin timespec
evaluates to true if the modified time of the file matches timespec (see the ”find” manual
page).
Support wildcards in file names
Anything else that seems useful to you
If you do any of the extra-credit items, be sure to provide your own gradefile.EXTRA input file
so I know what works.
Hints and Help
1. I’ve provided 2 example programs that will give you a good headstart on working with both
directories (readdir.c) and file information (sstat.c)
2. I’ve provided a tar file ”testdir.tar”. You should ”untar” that file into your source directory
and use that for testing. It contains lots of interesting cases. To ”untar” that file into your
current directory, type:
tar xvf testdir.tar
3. In all cases, if you’re not sure what your program is supposed to do, the answer is that it
should do exactly what the real ”find” program does in that case.
Example Input File
(this is from ”grademe.required”)
./find testdir/dir1/subdir1
./find testdir
./find testdir -type d
./find testdir -type f
./find testdir -type f -size +100c
./find testdir -name gf100
./find testdir -type d -name subsubdir3
./find testdir -type f -name subsubdir3
