Linux Ask! is a Q & A web site specific for Linux related questions. Questions are collected, answered and audited by experienced Linux users.
Kill all processes accessing the a particular file/folder
Answer:
To kill all processes accessing the a particular file/folder, you can use the follow command:
# /sbin/fuser -k /data/backup
It is very useful when you want to unmount a filesystem but Linux reported the device is busy.
How to avoid command being saved to shell history
Answer:
Firstly, you need to set the Bash shell environment variable to tell the shell to ignore the history if the command is starting with a particular character, e.g. a space in our case below.
# export HISTIGNORE="&:[ ]*"
Then, type the command start with a space
# who
And verify using the history command
# history
Best way to kill all child processes forked by a given program
Answer:
Firstly, find the process group leader (i.e. master process that forked other processes) of the program, e.g. apache2
# sudo ps x -o "%p %r %y %x %c " | grep apache2
14787 14787 ? 00:00:00 apache2
To verify if it is the process leader.
# pgrep apache2 | sort -n | head -n1
14787
To issue kill to all the members in the process group
# kill -9 -14787
How to check the startup time of a particular program
Answer:
E.g. To check the startup time of MySQL server:
# ps -eo pid,user,cmd,lstart | grep /sbin/mysqld
3546 mysql /usr/sbin/mysqld --basedir= Tue Mar 30 21:29:12 2010
9195 root grep /sbin/mysqld Tue Mar 30 22:43:33 2010
How to convert ext2 partition to ext3?
Answer:
Firstly, you need to create a journal on it. This can be done either the file system is mounted or unmounted.
# tune2fs -j /dev/hdaX
Then, mount the filesystem as ext3
# mount -t ext3 /dev/hdaX /mnt/somewhere
Reference: http://batleth.sapienti-sat.org/projects/FAQs/ext3-faq.html
