supports the find command traversing directory file trees - i.e., searching and locating files.
Assuming you want to keep the command you already have (and I am not sue that Rudi's suggested test is valid because of file and directory caching ):
A limiting factor is known to be the number of sub-directories in the file tree, and possibly the number of available open file descriptors - a per process limit.
If you can parallelize your code using several processes it may improve performance. I'm not sure this will help much because it depends on the number of sub-directories being large to gain any benefit. The developers who write system code try to maximize throughput.
What I'm saying is: performance enhancement work is subjective and often a misplaced resource and a waste of programmer time.
Suppose your command runs in one minute in production. Then you work hard and get it down to 35 seconds. The user perception of "slow" will still be there, so you have to get it down to maybe 6 seconds to make users happy and see it as "faster". In this case getting an order of magnitude improvement may not be possible.
And in this case you would have to do something about directory caching messing up testing because (you check this yourself) once you open a directory the system caches it for speedier access. Use the time command and rerun the command to see what I mean:
This User Gave Thanks to jim mcnamara For This Post:
Hi ,
i'm searching for files over many Aix servers with rsh command using this request :
find /dir1 -name '*.' -exec ls {} \;
and then count them with "wc"
but i would improve this search because it's too long and replace directly find with ls command but "ls *. " doesn't work.
and... (3 Replies)
I have written a code using AWK & sed to compare two files.
The structure of the files is like this"
Format is this:
<bit code> <file code> <string>
Follwoed by any numbers of properties lines whic start with a "space"
10101010101111101 XX abcd a
AS sasa
BS kkk
1110000101010110 XX... (1 Reply)
I'm using sed to do find and replace. But since the file is huge and i have more than 1000 files to be searched, the script is taking a lot of time. Can somebody help me with a better sed command. Below is the details.
Input:
1
1
2
3
3
4
5
5
Here I know the file is sorted.
... (4 Replies)
Hi,
I wanted to run a particlar script for every 20 minutes. I dont have crontab in my server. Hence i ran this script in a loop by providing the command sleep 1200
Now i wanted to know is there any performance issue if this job keeps on execute in the server.
Thanks,
Puni (1 Reply)
Hi,
I have created a shell script for Server Log Automation Process. I have used
find xargs grep command to search the string.
for Example,
find -name | xargs grep "816995225" > test.txt .
Here my problem is,
We have lot of records and we want to grep the string... (4 Replies)
Hello All,
We have a working script which identifies and kills ipcs resources which havent been correctly killed during normal shutdowns.
It is working fine and dandy however there are some issues now.
Environment:
SunOS 5.10 Generic_148888-03 sun4u sparc SUNW,SPARC-Enterprise
... (4 Replies)
I have a ksh shell script and i need to pass arguments which are generated by data pulled from a database.
When the argument to the shell script is too long (about 4000 charecters) the below is the issue observed.
I copy the command which is 4000 charecters long from the logs and paste it... (7 Replies)
Discussion started by: mohtashims
7 Replies
LEARN ABOUT OSX
ftw
FTW(3) BSD Library Functions Manual FTW(3)NAME
ftw, nftw -- traverse (walk) a file tree
SYNOPSIS
#include <ftw.h>
int
ftw(const char *path, int (*fn)(const char *, const struct stat *ptr, int flag), int depth);
int
nftw(const char *path, int (*fn)(const char *, const struct stat *ptr, int flag, struct FTW *), int depth, int flags);
DESCRIPTION
These functions are provided for compatibility with legacy code. New code should use the fts(3) functions.
The ftw() and nftw() functions traverse (walk) the directory hierarchy rooted in path. For each object in the hierarchy, these functions
call the function pointed to by fn. The ftw() function passes this function a pointer to a NUL-terminated string containing the name of the
object, a pointer to a stat structure corresponding to the object, and an integer flag. The nftw() function passes the aforementioned argu-
ments plus a pointer to a FTW structure as defined by <ftw.h> (shown below):
struct FTW {
int base; /* offset of basename into pathname */
int level; /* directory depth relative to starting point */
};
Possible values for the flag passed to fn are:
FTW_F A regular file.
FTW_D A directory being visited in pre-order.
FTW_DNR A directory which cannot be read. The directory will not be descended into.
FTW_DP A directory being visited in post-order (nftw() only).
FTW_NS A file for which no stat(2) information was available. The contents of the stat structure are undefined.
FTW_SL A symbolic link.
FTW_SLN A symbolic link with a non-existent target (nftw() only).
The ftw() function traverses the tree in pre-order. That is, it processes the directory before the directory's contents.
The depth argument specifies the maximum number of file descriptors to keep open while traversing the tree. It has no effect in this imple-
mentation.
The nftw() function has an additional flags argument with the following possible values:
FTW_PHYS Physical walk, don't follow symbolic links.
FTW_MOUNT The walk will not cross a mount point.
FTW_DEPTH Process directories in post-order. Contents of a directory are visited before the directory itself. By default, nftw() traverses
the tree in pre-order.
FTW_CHDIR Change to a directory before reading it. By default, nftw() will change its starting directory. The current working directory
will be restored to its original value before nftw() returns.
RETURN VALUES
If the tree was traversed successfully, the ftw() and nftw() functions return 0. If the function pointed to by fn returns a non-zero value,
ftw() and nftw() will stop processing the tree and return the value from fn. Both functions return -1 if an error is detected.
ERRORS
The ftw() and nftw() functions may fail and set errno for any of the errors specified for the library functions close(2), open(2), stat(2),
malloc(3), opendir(3) and readdir(3). If the FTW_CHDIR flag is set, the nftw() function may fail and set errno for any of the errors speci-
fied for chdir(2). In addition, either function may fail and set errno as follows:
[EINVAL] The depth argument is less than 1 or greater than OPEN_MAX.
LEGACY ERRORS
The ftw() and nftw() functions are far more tolerant of symlink cycles and are lax in reporting errors while accessing the initial path.
When nftw() is passed FTW_MOUNT, it will pass the mount point to the callback function.
SEE ALSO chdir(2), close(2), open(2), stat(2), fts(3), malloc(3), opendir(3), readdir(3), compat(5)STANDARDS
The ftw() and nftw() functions conform to IEEE Std 1003.1-2001 (``POSIX.1'') and Version 3 of the Single UNIX Specification (``SUSv3'').
HISTORY
Prior to MacOS X 10.4 ftw did not follow symlinks.
BUGS
The depth argument is currently ignored.
BSD May 20, 2003 BSD