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Tuesday, May 15, 2012

ls command delays in displaying output


Step 1:
We face issues and we tend to find an answer.
Step 2:
We get the answer and we resolve the issue.
Step 3:(Optional and always ignored)
I think its a time to document it . You will find all such instances under Problem and Answer section.



Back in october 2011 i faced a strange issue while listing the files.

I fire my favorite command to display the files/folders


#ls -ltr

to my surprise my system hanged for some time and there was significant delay in showing the output(Delay of 3 minute 2 sec. )

#time ls -ltr 
real 3m2.443s
user 0m0.003s 
sys 0m0.002s

I checked the load on system but it was within the accepted level .

Later i just issued ls command without -l option and everything looked ok.

#time ls 
real 0m0.004s
user 0m0.000s
sys 0m0.002s

This was something i never encountered before so i raised queries regarding the same on almost all linux forum.
http://www.linuxforums.org/forum/newbie/180596-execution-delay-listing-files.html#post851886

Some of the answers were really worth mentioning here.
1) the aliased "ls" command may be at fault.
Try running the command "/bin/ls -ltr" and see how that works.

2)Well the t flag sorts by modification time and then the r flag reverses the order, so maybe if there are a lot of files in that directory the sort is taking time, try running the following to identify which flag is slowing it down time ls
time ls -l 
time ls -t 
time ls -r

Answer:

The actual problem was of incorrect ownership of one of the folder. When i tried executing ls -n it resulted in faster responce . -n option make sure that only uid and gid are displayed. I figured out that one of the folder had wrong ownership. I changed the ownership of the folder and the problem was solved.
 

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