Frequently Asked Questions About Linux / UNIX » Linux http://www.cyberciti.biz/faq Every answer asks a more beautiful question. Fri, 03 Feb 2012 22:38:32 +0000 en hourly 1 http://wordpress.org/?v=3.3.1 Linux / Unix: SysVinit Services Restart vs Reload vs Condrestarthttp://www.cyberciti.biz/faq/linux-unix-sysvinit-services-restart-vs-reload-vs-condrestart/ http://www.cyberciti.biz/faq/linux-unix-sysvinit-services-restart-vs-reload-vs-condrestart/#comments Thu, 05 Jan 2012 21:24:25 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=11349 Can you tell me differences between the following sysvinit /sbin/service command:
service httpd restart service httpd condrestart service httpd reload
]]> http://www.cyberciti.biz/faq/linux-unix-sysvinit-services-restart-vs-reload-vs-condrestart/feed/ 0 Linux: Find Out Open Files [ Descriptors ] Commandhttp://www.cyberciti.biz/faq/linux-find-total-open-files-descriptors/ http://www.cyberciti.biz/faq/linux-find-total-open-files-descriptors/#comments Wed, 04 Jan 2012 18:25:02 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=11334 How do I find out that how many files are open and how many allowed in Linux server operating systems?]]> http://www.cyberciti.biz/faq/linux-find-total-open-files-descriptors/feed/ 2 Linux: Find Out What Partition a File Belongs Tohttp://www.cyberciti.biz/faq/linux-unix-command-findout-on-which-partition-file-directory-exits/ http://www.cyberciti.biz/faq/linux-unix-command-findout-on-which-partition-file-directory-exits/#comments Mon, 19 Dec 2011 20:18:00 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=11270 How do I find out that /users/f/foo/file.txt file belongs to a specific partition?]]> http://www.cyberciti.biz/faq/linux-unix-command-findout-on-which-partition-file-directory-exits/feed/ 1 Linux: Neighbour Table Overflow Error and Solutionhttp://www.cyberciti.biz/faq/centos-redhat-debian-linux-neighbor-table-overflow/ http://www.cyberciti.biz/faq/centos-redhat-debian-linux-neighbor-table-overflow/#comments Mon, 19 Dec 2011 19:39:11 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=11265 I setup a CentOS Linux based Linux server running as a gateway and firewall server. However, I'm getting the following messages in the /var/log/messages log file:
Dec 20 00:41:01 fw01 kernel: Neighbour table overflow. Dec 20 00:41:01 fw01 last message repeated 20 times
OR
Dec 20 00:41:01 fw03 kernel: [ 8987.821184] Neighbour table overflow. Dec 20 00:41:01 fw03 kernel: [ 8987.860465] printk: 100 messages suppressed.
Why does kernel throw "Neighbour table overflow" messages in syslog? How do I fix this problem under Debian / CentOS / RHEL / Fedora / Ubuntu Linux?]]> http://www.cyberciti.biz/faq/centos-redhat-debian-linux-neighbor-table-overflow/feed/ 0 Linux: Run fsck On LUKS (dm-crypt) Based LVM Physical Volumehttp://www.cyberciti.biz/faq/howto-centos-rhel-fedora-debian-fsck-ext3-on-luks-volume/ http://www.cyberciti.biz/faq/howto-centos-rhel-fedora-debian-fsck-ext3-on-luks-volume/#comments Tue, 06 Dec 2011 07:54:56 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=11227 I'm using dm-crypt based transparent disk encryption subsystem in Linux. The cryptsetup command is used deal with the Linux Unified Key Setup (LUKS) on-disk format and mount the partition. My setup includes RAID-10 with an LVM physical volume. How do I run fsck ("file system check") on dm-crypt / LUKS based LVM physical volume under Linux operating systems?]]> http://www.cyberciti.biz/faq/howto-centos-rhel-fedora-debian-fsck-ext3-on-luks-volume/feed/ 0 Linux: Reset High Speed USB Device Using ehci_hcd Error and Solutionhttp://www.cyberciti.biz/faq/rhel-redhat-centos-kernel-usb-reset-high-speed-ehci_hcd/ http://www.cyberciti.biz/faq/rhel-redhat-centos-kernel-usb-reset-high-speed-ehci_hcd/#comments Thu, 13 Oct 2011 22:35:21 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=11170 I've recently installed CentOS / RHEL 6.x on the server. I'm getting the following messages in /var/log/messages file logged frequently :
Oct 13 14:00:20 server1 kernel: usb 1-7: reset high speed USB device using ehci_hcd and address 2 Oct 13 14:05:57 server1 kernel: usb 1-7: reset high speed USB device using ehci_hcd and address 2 Oct 13 14:09:18 server1 kernel: usb 1-7: reset high speed USB device using ehci_hcd and address 2 Oct 13 14:11:42 server1 kernel: usb 1-7: reset high speed USB device using ehci_hcd and address 2 Oct 13 14:11:49 server1 kernel: usb 1-7: reset high speed USB device using ehci_hcd and address 2
How do I solve this problem?]]> http://www.cyberciti.biz/faq/rhel-redhat-centos-kernel-usb-reset-high-speed-ehci_hcd/feed/ 1 Mplayer Shuffle Command: Play Files In Random Orderhttp://www.cyberciti.biz/faq/mplayer-shuffle-ubuntu-redhat-fedora-debian-bsd/ http://www.cyberciti.biz/faq/mplayer-shuffle-ubuntu-redhat-fedora-debian-bsd/#comments Sat, 01 Oct 2011 12:44:08 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=11147 How do I play files in random order using the mplayer command line player under Linux / Unix operating systems?]]> http://www.cyberciti.biz/faq/mplayer-shuffle-ubuntu-redhat-fedora-debian-bsd/feed/ 7 Linux: Mount Disk Partition Using LABELhttp://www.cyberciti.biz/faq/rhel-centos-debian-fedora-mount-partition-label/ http://www.cyberciti.biz/faq/rhel-centos-debian-fedora-mount-partition-label/#comments Thu, 22 Sep 2011 10:09:36 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=11126 How do I mount the filesystem (disk partition) using the filesystem label on the ext3/ext4 file system located on USB disk or hard disk under Linux operating systems?]]> http://www.cyberciti.biz/faq/rhel-centos-debian-fedora-mount-partition-label/feed/ 1 Linux / Unix: Bash Find Matching All Dot Fileshttp://www.cyberciti.biz/faq/linux-unix-bsd-appleosx-ksh-csh-bash-find-hidden-dotfiles/ http://www.cyberciti.biz/faq/linux-unix-bsd-appleosx-ksh-csh-bash-find-hidden-dotfiles/#comments Wed, 14 Sep 2011 06:18:12 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=11078 A dot-file is generally any file whose name begins with a full stop. In Linux or Unix like operating system it is also called as hidden file. How do I list all dot files in my home directory?]]> http://www.cyberciti.biz/faq/linux-unix-bsd-appleosx-ksh-csh-bash-find-hidden-dotfiles/feed/ 4 Linux / Unix: Find Out What tty I’m Usinghttp://www.cyberciti.biz/faq/linux-unix-appleosx-bsd-what-tty-command/ http://www.cyberciti.biz/faq/linux-unix-appleosx-bsd-what-tty-command/#comments Wed, 14 Sep 2011 06:05:23 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=11067 What is a tty under Linux / UNIX? How do I find out what tty I'm on?]]> http://www.cyberciti.biz/faq/linux-unix-appleosx-bsd-what-tty-command/feed/ 0 Linux: NFS4 mount Error reason given by server: No such file or directoryhttp://www.cyberciti.biz/faq/mount-nfs4-reason-given-by-server-no-such-file-directory/ http://www.cyberciti.biz/faq/mount-nfs4-reason-given-by-server-no-such-file-directory/#comments Tue, 06 Sep 2011 23:41:49 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=11006 I recently installed NFS server v4 on my HP Linux server. However, I'm not able to mount it from Linux nfs4 client using the following command:
mount.nfs4 server2:/data /data
I'm getting the following error:
mount.nfs4: mounting server2:/data failed, reason given by server: No such file or directory
How do I fix this problem?]]> http://www.cyberciti.biz/faq/mount-nfs4-reason-given-by-server-no-such-file-directory/feed/ 0 JBD: Barrier-based Sync Failed On md0-8 – Disabling Barriers Error and Solutionhttp://www.cyberciti.biz/faq/rhel-fedora-debian-ubuntui-linuxjbd-barrier-sync-failed/ http://www.cyberciti.biz/faq/rhel-fedora-debian-ubuntui-linuxjbd-barrier-sync-failed/#comments Sun, 04 Sep 2011 21:21:43 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=10990 I've used the mdadm command line utility to setup and manage software RAID 6 under Debian Linux server. However, I get the following message in /var/log/messages file: [ 14.003707] JBD: barrier-based sync failed on md0-8 - disabling barriers How do I fix the message 'JBD error message "barrier-based sync failed"'? ]]> http://www.cyberciti.biz/faq/rhel-fedora-debian-ubuntui-linuxjbd-barrier-sync-failed/feed/ 2 Linux Delete / Remove MBRhttp://www.cyberciti.biz/faq/linux-clearing-out-master-boot-record-dd-command/ http://www.cyberciti.biz/faq/linux-clearing-out-master-boot-record-dd-command/#comments Fri, 12 Aug 2011 21:51:32 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=10907 I've installed an usb image on Pen drive along with MBR. Now, I need to use this USB pen for other purpose. Is there a way in Linux to delete the mbr (just like dos fdisk /mbr command)?]]> http://www.cyberciti.biz/faq/linux-clearing-out-master-boot-record-dd-command/feed/ 2 Linux Download Password Protected Large ISO Images [ Authentication Credentials ]http://www.cyberciti.biz/faq/linux-download-manager-authentication-credentials-username-password/ http://www.cyberciti.biz/faq/linux-download-manager-authentication-credentials-username-password/#comments Thu, 28 Jul 2011 12:56:58 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=10898 I'm trying to download an ISO image for Enterprise Linux from RHN or Novell Suse. Both providers have placed ISO images behind paywall. I need to provide authentication credentials before downloading all files. How do I download ISO files using the wget command with user name and password?]]> http://www.cyberciti.biz/faq/linux-download-manager-authentication-credentials-username-password/feed/ 7 Remote Shutdown of a Linux / Unix Computer From MS-Windowshttp://www.cyberciti.biz/faq/shutdown-remote-linux-server-pc-from-windows-computer/ http://www.cyberciti.biz/faq/shutdown-remote-linux-server-pc-from-windows-computer/#comments Wed, 13 Jul 2011 07:00:59 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=10820 How do I shutdown remote Linux or UNIX system from MS-Windows system? ]]> http://www.cyberciti.biz/faq/shutdown-remote-linux-server-pc-from-windows-computer/feed/ 0 Slow DNS on Linux with IPv4 and IPV6 Configured Firewallhttp://www.cyberciti.biz/faq/rhel-redhat-centos-slow-dns-on-linux-with-ipv6-configured-firewall/ http://www.cyberciti.biz/faq/rhel-redhat-centos-slow-dns-on-linux-with-ipv6-configured-firewall/#comments Mon, 04 Jul 2011 05:23:11 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=10790 I'm getting slow DNS response from ssh and other network related traffic with delay of 30-60+ seconds per connection. All of our servers are behind hardware based dedicated firewall. My RHEL v6.1 server system running on HP hardware. How do I fix this problem?]]> http://www.cyberciti.biz/faq/rhel-redhat-centos-slow-dns-on-linux-with-ipv6-configured-firewall/feed/ 0 Linux: Dell Server / Desktop / Laptop Find Out Service Tag Commandhttp://www.cyberciti.biz/faq/linux-find-dell-service-tag-command/ http://www.cyberciti.biz/faq/linux-find-dell-service-tag-command/#comments Mon, 04 Jul 2011 03:41:51 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=10786 I need to find out the service tag of my Dell server or computer. How do I find out my nique five- to seven- digit alphanumeric (letter and number) service tag code without looking on the back of the system or opening door of bezel?]]> http://www.cyberciti.biz/faq/linux-find-dell-service-tag-command/feed/ 2 Linux: Find All File Descriptors Used By a Processhttp://www.cyberciti.biz/faq/linux-find-all-file-descriptors-used-by-a-process/ http://www.cyberciti.biz/faq/linux-find-all-file-descriptors-used-by-a-process/#comments Fri, 01 Jul 2011 23:06:46 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=10773 How can I find all the file descriptors used by a process such as httpd (Apache web server) or mysqld (MySQL Database server)?]]> http://www.cyberciti.biz/faq/linux-find-all-file-descriptors-used-by-a-process/feed/ 1 Linux / UNIX: Smartctl Check Hard Disk Behind 3Ware RAID Cardhttp://www.cyberciti.biz/faq/unix-linux-freebsd-3w-9xxx-smartctl-check-hard-disk-command/ http://www.cyberciti.biz/faq/unix-linux-freebsd-3w-9xxx-smartctl-check-hard-disk-command/#comments Sat, 25 Jun 2011 13:49:00 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=10759 I've CentOS Linux and FreeBSD based server running using 3Ware (9650SE-2LP) RAID card. I know how to check hard disk behind Adaptec raid controllers, but how do I look at ATA / SATA disks behind 3ware SCSI RAID controllers using smartctl command?]]> http://www.cyberciti.biz/faq/unix-linux-freebsd-3w-9xxx-smartctl-check-hard-disk-command/feed/ 0 Linux: Delete / Remove User Accounthttp://www.cyberciti.biz/faq/linux-remove-user-command/ http://www.cyberciti.biz/faq/linux-remove-user-command/#comments Thu, 16 Jun 2011 00:19:07 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=10710 How do I remove a user's access from my server? How do I delete a user account under Linux operating systems?]]> http://www.cyberciti.biz/faq/linux-remove-user-command/feed/ 1