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curiosity in df command and pipe

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ogniemi

ogniemi

Technical User
Nov 7, 2003
1,041
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# for i in 1 2 3 4 5;do df -sk /home ; df -sk | grep -w /home$;echo "";done
Filesystem 1024-blocks Free* %Used Iused %Iused Mounted on
/dev/hd1 4587520 483180 90% 4171 4% /home
/dev/hd1 4587520 1920412 59% 4081 1% /home

Filesystem 1024-blocks Free* %Used Iused %Iused Mounted on
/dev/hd1 4587520 483180 90% 4171 4% /home
/dev/hd1 4587520 1920412 59% 4081 1% /home

Filesystem 1024-blocks Free* %Used Iused %Iused Mounted on
/dev/hd1 4587520 483180 90% 4171 4% /home
/dev/hd1 4587520 1920412 59% 4081 1% /home

Filesystem 1024-blocks Free* %Used Iused %Iused Mounted on
/dev/hd1 4587520 483180 90% 4171 4% /home
/dev/hd1 4587520 1920412 59% 4081 1% /home

Filesystem 1024-blocks Free* %Used Iused %Iused Mounted on
/dev/hd1 4587520 483180 90% 4171 4% /home
/dev/hd1 4587520 1920412 59% 4081 1% /home


Anyone know the explaination?
 
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ogniemi,

What do you really wants to be explained?

if you separate the for loop like that then you will see how this was translated into the output you've got

Code: 
for i in 1 2 3 4 5;
do 
df -sk /home;
df -sk | grep -w /home$;
echo "";
done

so that's why you are getting two lines for /home!
one for df -sk /home;
and the other for df -sk | grep -w /home$;

is that what you want?

Regards,
Khalid
 
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please compare these two lines - one got with "df -sk /home" and the other with "df -sk | grep -w /home$"

two lines linked to the same filesystem /home but different Free, %Usage, Iused, $Iused

That was my question, why lines are different...
 
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hmmmm

Interesting!!!

I ran the same command on my machine and this is the output i got:

Code: 
# for i in 1 2 3 4 5;do df -sk /home ; df -sk | grep -w /home$;echo "";done
Filesystem    1024-blocks     Free* %Used    Iused %Iused Mounted on
/dev/hd1           262144    260368    1%      166     1% /home
/dev/hd1           262144    260368    1%      166     1% /home

Filesystem    1024-blocks     Free* %Used    Iused %Iused Mounted on
/dev/hd1           262144    260368    1%      166     1% /home
/dev/hd1           262144    260368    1%      166     1% /home

Filesystem    1024-blocks     Free* %Used    Iused %Iused Mounted on
/dev/hd1           262144    260368    1%      166     1% /home
/dev/hd1           262144    260368    1%      166     1% /home

Filesystem    1024-blocks     Free* %Used    Iused %Iused Mounted on
/dev/hd1           262144    260368    1%      166     1% /home
/dev/hd1           262144    260368    1%      166     1% /home

Filesystem    1024-blocks     Free* %Used    Iused %Iused Mounted on
/dev/hd1           262144    260368    1%      166     1% /home
/dev/hd1           262144    260368    1%      166     1% /home

????

so its exactly the same!!!

Regards,
Khalid
 
Upvote 0 Downvote
I run on two different my systems and the output is not the same


# for i in 1 2 3 4 5;do df -sk /home ; df -sk | grep -w /home$;echo "";done
Filesystem 1024-blocks Free* %Used Iused %Iused Mounted on
/dev/hd1 393216 288200 27% 1815 3% /home
/dev/hd1 393216 288588 27% 1815 3% /home

Filesystem 1024-blocks Free* %Used Iused %Iused Mounted on
/dev/hd1 393216 288200 27% 1815 3% /home
/dev/hd1 393216 288588 27% 1815 3% /home

Filesystem 1024-blocks Free* %Used Iused %Iused Mounted on
/dev/hd1 393216 288200 27% 1815 3% /home
/dev/hd1 393216 288588 27% 1815 3% /home

Filesystem 1024-blocks Free* %Used Iused %Iused Mounted on
/dev/hd1 393216 288200 27% 1815 3% /home
/dev/hd1 393216 288588 27% 1815 3% /home

Filesystem 1024-blocks Free* %Used Iused %Iused Mounted on
/dev/hd1 393216 288200 27% 1815 3% /home
/dev/hd1 393216 288588 27% 1815 3% /home


# for i in 1 2 3 4 5;do df -sk /home ; df -sk | grep -w /home$;echo "";done
Filesystem 1024-blocks Free* %Used Iused %Iused Mounted on
/dev/hd1 524288 301596 43% 2567 4% /home
/dev/hd1 524288 301448 43% 2606 4% /home

Filesystem 1024-blocks Free* %Used Iused %Iused Mounted on
/dev/hd1 524288 301596 43% 2567 4% /home
/dev/hd1 524288 301448 43% 2606 4% /home

Filesystem 1024-blocks Free* %Used Iused %Iused Mounted on
/dev/hd1 524288 301596 43% 2567 4% /home
/dev/hd1 524288 301448 43% 2606 4% /home

Filesystem 1024-blocks Free* %Used Iused %Iused Mounted on
/dev/hd1 524288 301596 43% 2567 4% /home
/dev/hd1 524288 301448 43% 2606 4% /home

Filesystem 1024-blocks Free* %Used Iused %Iused Mounted on
/dev/hd1 524288 301596 43% 2567 4% /home
/dev/hd1 524288 301448 43% 2606 4% /home


can you try on other hosts?
 
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Code: 
# for i in 1 2 3 4 5;do df -sk /home ; df -sk | grep -w /home$;echo "";done
Filesystem    1024-blocks     Free* %Used    Iused %Iused Mounted on
/dev/hd1           262144    261760    1%        5     1% /home
/dev/hd1           262144    261760    1%        5     1% /home

Filesystem    1024-blocks     Free* %Used    Iused %Iused Mounted on
/dev/hd1           262144    261760    1%        5     1% /home
/dev/hd1           262144    261760    1%        5     1% /home

Filesystem    1024-blocks     Free* %Used    Iused %Iused Mounted on
/dev/hd1           262144    261760    1%        5     1% /home
/dev/hd1           262144    261760    1%        5     1% /home

Filesystem    1024-blocks     Free* %Used    Iused %Iused Mounted on
/dev/hd1           262144    261760    1%        5     1% /home
/dev/hd1           262144    261760    1%        5     1% /home

Filesystem    1024-blocks     Free* %Used    Iused %Iused Mounted on
/dev/hd1           262144    261760    1%        5     1% /home
/dev/hd1           262144    261760    1%        5     1% /home

Code: 
# for i in 1 2 3 4 5;do df -sk /home ; df -sk | grep -w /home$;echo "";done
Filesystem    1024-blocks     Free* %Used    Iused %Iused Mounted on
/dev/hd1           262144    261760    1%        5     1% /home
/dev/hd1           262144    261724    1%       11     1% /home

Filesystem    1024-blocks     Free* %Used    Iused %Iused Mounted on
/dev/hd1           262144    261760    1%        5     1% /home
/dev/hd1           262144    261724    1%       11     1% /home

Filesystem    1024-blocks     Free* %Used    Iused %Iused Mounted on
/dev/hd1           262144    261760    1%        5     1% /home
/dev/hd1           262144    261724    1%       11     1% /home

Filesystem    1024-blocks     Free* %Used    Iused %Iused Mounted on
/dev/hd1           262144    261760    1%        5     1% /home
/dev/hd1           262144    261724    1%       11     1% /home

Filesystem    1024-blocks     Free* %Used    Iused %Iused Mounted on
/dev/hd1           262144    261760    1%        5     1% /home
/dev/hd1           262144    261724    1%       11     1% /home

oh yeah that was different!!!

Code: 
# for i in 1 2 3 4 5;do df -sk /home ; df -sk | grep -w /home$;echo "";done
Filesystem    1024-blocks     Free* %Used    Iused %Iused Mounted on
/dev/hd1           131072    130708    1%        5     1% /home
/dev/hd1           131072    130708    1%        5     1% /home

Filesystem    1024-blocks     Free* %Used    Iused %Iused Mounted on
/dev/hd1           131072    130708    1%        5     1% /home
/dev/hd1           131072    130708    1%        5     1% /home

Filesystem    1024-blocks     Free* %Used    Iused %Iused Mounted on
/dev/hd1           131072    130708    1%        5     1% /home
/dev/hd1           131072    130708    1%        5     1% /home

Filesystem    1024-blocks     Free* %Used    Iused %Iused Mounted on
/dev/hd1           131072    130708    1%        5     1% /home
/dev/hd1           131072    130708    1%        5     1% /home

Filesystem    1024-blocks     Free* %Used    Iused %Iused Mounted on
/dev/hd1           131072    130708    1%        5     1% /home
/dev/hd1           131072    130708    1%        5     1% /home

hmmmmmm

its getting more interesting :)
 
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I believe the first df -sk /home is looking into whatever inside the home directory but df -sk | grep -w /home is including /home with it!!! so that explains the Iused and %Iused differences???!!!

:)
 
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FYI
on my AIX 5.2

df -sk /usr
Filesystem 1024-blocks Free* %Used Iused %Iused Mounted on
/dev/hd2 6689789819698944 0 100% 4096 100% /usr

df -sk | grep usr
/dev/hd2 3145728 1557588 51% 32402 5% /usr

WOW! 100% used
 
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on my side I'd observed it on

# oslevel -s
5200-08-01

# oslevel -s
5300-04-01


 
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Hi

In documentations it says:
-s Gets file system statistics from the VFS specific file system helper instead of the statfs system call. Any arguments given when using the -s flag must be a JFS or Enhanced JFS filesystem mount point or device. The filesystem must also be listed in /etc/filesystems.

But it does not explain why the differance, but the information is collected with different methods :-(

Could it be odm problem, what happend if synclvodm is issued ?

/HGA
 
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On the other hand I can't reproduce it on my AIX 5.1 systems. Does it make any difference if you use 'df -k' as opposed to 'df -sk'?

Ceci n'est pas une signature
Columb Healy
 
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AIX 5.2

df -k is OK
it is definately the -s option that screws it up
 
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