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grep pattern interpretted differently in 2 different systems with same grep version

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http://serverfault.com – We manufacture a linux appliance for data centers, and all are running fedora installed from the same kickstart process. There are different hardware versions, some with IDE hard drives and some SCSI, so the filesystems may be at /dev/sdaN or /dev/hdaN. We have a web interface into these appliances that show disk usage, which is generated using "df | grep /dev/*da". This generally works for both hardware versions, giving an output like follows: /dev/sda2 5952284 3507816 2137228 63% / /dev/sda5 67670876 9128796 55049152 15% /data /dev/sda1 (HowTos)

xskl's picture
Submitted by xskl on 09/25/2012

Stories similar to grep pattern interpretted differently in 2 different systems with same grep version

I am trying to understand the difference between grep -e and grep -E.

xaos52 wrote:Post output from lspci -knn | grep -EiA2 to see the wifi chipset.Thanks Doc: but there might be sthg missing from your code ... or?tantric tex # lspci -knn | grep -EiA2 Usage: grep [OPTION]... PATTERN [FILE]... Try `grep --help' for more information.?Tex-turbed

I want to grep a pattern in some files and count the occurrence with the filename. Right know, if I use

grep -r "month" report* | wc -l

it will sum all instances in all files. So the output is a single value 324343. I want something like this

report1: 3433 report2: 24399 ....

The grep command will show the filename but will print every instance.

I would like to get the multi pattern match with implicit AND between patterns, i.e. equivalent to running several greps in a sequence:

grep pattern1 | grep pattern2 | ...

So how to convert it to something like?

grep pattern1 & pattern2 & pattern3

I would like to use single grep because I am building arguments dynamically, so everything has to fit in one string.

Hey Everyone,

I'm having a really hard time figuring this one out.

Using the top command with redirection works fine:

top > top.log

Now I want to use grep to filter a certain line:

top | grep "my_program" > top.log

But the log file will remain empty. But grep delivers an output when using

top | grep "my_program"

Where my_program has to be replaced by a running program to see some output.

Why does my approach not work ? And how can I fix it ?

alternative to the grep trick 1 year 21 weeks ago

Hi,

We used to use the below commands often.

Code: ps -ef|grep [a]bc ps -ef|grep abc|grep -v grep Both fairly returns the same result. For example, the process name is dynamic and we are having the process name in a variable, how we can apply the above trick.

For example "a" is the variable which contains the process name abc, then

Code: ps -ef|grep $a|grep -v grep This w

The following script is meant to output "vmstat" for example every 15 seconds, but for some reason it only does this if there's activity or when I kill the script, in other cases it just sits there.

#!/bin/bash #!/bin/sh

ps -ef | grep -v grep | grep "vmstat 15" | awk '{ print $2 }' | xargs kill

ps -ef | grep -v grep | grep "iostat 15" | awk '{ print $2 }' | xargs kill

ps -ef | grep -v grep |

Grep error in Bashscript 2 years 45 weeks ago

While running bashscript i.e. checkdump I am getting error.

Quote:

#cat checkdump #!/bin/bash cd /dump_restore/outputs/dump/daily/ dt=date | awk '{print $2}'

echo "########Checktime#######" ls -ltr | tail -1 | awk '{print "cat " $9}' | sh | grep $dt

Output