Linux Ask! is a Q & A web site specific for Linux related questions. Questions are collected, answered and audited by experienced Linux users.
Immediate time synchronization in RHEL/CentOS/Fedora
Answer:
If you want to sync the system time without installing ntpd package, rdate is an older way but it will do what you need.
# rdate -s ntp0.cornell.eduYou can find a list of time servers at: http://pank.org/blog/2004/08/time-server-list.html
How to get the IP address assigned to eth0 by a single command
Answer:
Only a single command is needed to return only the IP address assigned to eth0:
# echo $(ifconfig eth0 | awk -F: '/inet addr:/ {print $2}' | awk '{ print $1 }')
58.23.182.42
sed: replace in place
Answer:
Newer version of sed allow you replace a file in place, no more redirection is needed.
# sed -i 's/abc/def/g' test.txt
The above command will replace all "abc" to "def" in the file test.txt
How to get the file creation time?
Answer:
Linux never stores file creation time.
You can only get access, modify & change (change of status, e.g. permission) time of a file with stats command
# stats test.txt
stat test.txt
File: `test.txt'
Size: 25557 Blocks: 56 IO Block: 4096 regular file
Device: ca01h/51713d Inode: 32714 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 1001/ user) Gid: ( 1000/ user)
Access: 2010-01-02 18:53:46.000000000 +0800
Modify: 1970-01-01 17:13:08.000000000 +0800
Change: 2010-01-02 18:53:46.000000000 +0800
Turn off PC speaker in Ubuntu Linux
Answer:
To turn of PC speaker so no more beep sound in Ubuntu
1. edit /etc/modprobe.d/blacklist
# sudo vi /etc/modprobe.d/blacklist
2. append the following line, save the file.
blacklist pcspkr
Restart your system to take effect.
