[SOLVED] command outputs more than I want

lucmove · 09-09-2009, 08:30 AM

Sometimes I like to check my partitions and see how many mounts I have until fsck is forced at boot (which takes a loooong time):

Code:

dumpe2fs /dev/sda5 | grep -i 'mount count'

So I made a script:

Code:

echo usr
dumpe2fs /dev/sda3 | grep -i 'mount count'
echo

echo home
dumpe2fs /dev/sda5 | grep -i 'mount count'
echo

echo backup
dumpe2fs /dev/sdb1 | grep -i 'mount count'
echo

And this is the output:

Code:

usr
dumpe2fs 1.40.8 (13-Mar-2008)
Mount count:              1
Maximum mount count:      20

home
dumpe2fs 1.40.8 (13-Mar-2008)
Mount count:              18
Maximum mount count:      20

backup
dumpe2fs 1.40.8 (13-Mar-2008)
Mount count:              18
Maximum mount count:      20

Why is that version and date string included in the output? It does not match my grep expression.

colucix · 09-09-2009, 08:38 AM

It prints the Version information to the standard error. Since only the standard output is sent through the pipe, the standard error is sent to the terminal, unless you redirect it to /dev/null or together with standard output through the pipe. Also note that if you use the option -h you will print out the header information only, reducing the time of execution:

Code:

dumpe2fs -h /dev/sda3 2>/dev/null | grep -i 'mount count'   # or
dumpe2fs -h /dev/sda3 2>&1 | grep -i 'mount count'

lucmove · 09-09-2009, 09:39 AM

Excellent! Thanks!