Linux Ask! is a Q & A web site specific for Linux related questions. Questions are collected, answered and audited by experienced Linux users.
What are its advantages in Ext4?
Answer:
See the complete lists of benefits here: http://en.wikipedia.org/wiki/Ext4#Features
One of the most important features is the called the delayed allocation.
Delayed allocation means delaying the block allocation process until the data is going to be written to the disk, which improves performance and reduces fragmentation.
How do I find out zombie process?
Answer
Use this command
# ps aux | awk '{ print $8 " " $2 }' | grep -w Z
It will give something like the following (The number is the zombie's pid)
Z 5938
Z 5485
...
Then we can kill it by using the pid
# kill -9 5938
Convert spaces into new lines using sed
Answer:
If you have a text file like:
1 2 3 4 5
How to convert the spaces into new lines?
Use sed!
# sed 's/ /\n/g' text.txt
How to replace multiple strings using sed?
Answer:
If you have multiple strings to replace, you can either using the "-e" option in sed, e.g.
sed -e 's/a/A/' -e 's/b/B/' < old.txt > new.txt
or, you can use a sed script file to store all the replace conditions
e.g. vi replace.sed
s/a/A/g
s/b/B/g
s/c/C/g
and execute like
sed -f replace.sed < old.txt > new.txt
How to make shell script run in low priority
Answer:
At the top of your shell script, add the following line (renice 19 -p $$)
#!/bin/sh
renice 19 -p $$
...
