RHCE Flashcards by http://systemnotes.org Free Information. Commands and procedures required for users of Redhat linux. Designed to help prepare for an RHCE exam based on RHEL5. Boot Single -- boot into single user mode. at grub screen, "a", "space", "1", enter Network Configuration system-config-network Files /etc/sysconfig/network-scripts/ifcfg-eth0 /etc/sysconfig/network Hostname Resolution /etc/resolv.conf /etc/hosts X Window System /etc/X11/xinit/xinitrc.d /etc/X11/xorg.conf /etc/inittab system-config-display /tmp and /home have enough space Ctrl-Alt-F1 to F8 Ctrl-Alt-Backspace Hard Disk Commands fdisk /dev/hda partprobe mdadm -C /dev/md0 -l 5 -n 3 /dev/hda6 /dev/hda7 /dev/hda8 mke2fs -j /dev/md0 e2label /dev/hda2 /data mount -t ext3 /dev/hda7 /data7 Configure Printing system-config-printer /etc/cups/cupsd.conf lpadmin lpstat, lpq reject disable accept /usr/bin/enable Cron and at Jobs copy script to /etc/cron.daily, /etc.cron.monthly, etc. or Modify /etc/crontab: crontab -e List cron jobs: crontab -l Add an at job: at [-f file] TIME View at queue: atq Remove at jog: atrm job Install NIS or LDAP Install ypbind, portmap system-config-authentication check: Enable NIS Support, or Enable LDAP Support click: Configure NIS..., or Configure LDAP... configure firewall, if required Test NIS or LDAP ypwhich nisdomainname -y genent services getent passwd smith rpcinfo -p NIS or LDAP Files /etc/yp.conf /etc/sysconfig/network /etc/pam.d/system-auth /etc/nsswitch.conf Configure autofs /etc/auto.master /home/guests /etc/auto.guests --timeout=60 /etc/auto.guests * -rw,soft,intr server1:/home/guests/& service autofs restart chkconfig portmap on chkconfig autofs on Manage Users, and Groups groupadd -g 1000 groupname useradd username usermod -G groupname username (-G for primary group) Manage Quotas quotacheck -cuf /home quotaon /home edquota username quota username repquota /home Filesystem Permissions mkdir -p /depts/finance chgrp sales /depts/finance chmod 770 /depts/* chmod g+s /depts/* chown sam /depts/managers ls -l /depts/ Install and Update rpms rpm -ivh filenamex.i386.rpm rpm -Uvh filenamex.i386.rpm Verify an RPM: rpm --import /usr/share/rhn/RPM-GPG-KEY rpm -K /tmp/rpmversion.i386.rpm Install from yum Repository /etc/yum.conf /etc/yum.repos.d/ System Bootloader /boot/grub/grub.conf # root (hd0,0) # kernel /vmlinuz-version ro root=/dev/vg00/lv00 crashkernel=128M@16M # initrd /initrd-version.img Implement Software RAID partprobe mdadm -C /dev/md0 -l 5 -n 3 /dev/hda6 /dev/hda7 /dev/hda8 mke2fs -j /dev/md0 /etc/fstab mdadm --detail /dev/md0 fail, recover, add: mdadm /dev/md0 -a /dev/sda1 Set Kernel Run-time Parameters vi /etc/sysctl.conf xxx.xx.xxx=1 sysctl -p sysctl -a | grep xxx Diagnose and Correct Boot Failures /etc/rc.d/rc.sysinit /etc/rc.d/rc adn /etc/rc.d/rc?.d /etc/rc.d/rc.local /boot/grub/grub.conf filesystem /etc/fstab fsck /dev/hda Create a Logical Volume First create physical volume, then volume group, then logical volume PV -> VG -> LV pvcreate /dev/hda6 /dev/hda7 /dev/hda8 vgcreate vg0 /dev/hda6 /dev/hda7 lvcreate -L 500M -n data0 vg0 ext2online /dev/vg0/data0 SELinux getenforce setenforce 1 check context with ls -Z chcon -R --reference /var/www/html /var/www/html/wwwnew Configure HTTP install httpd modify /etc/httpd/conf/httpd.conf file service httpd restart chkconfig httpd on service httpd configtest Configure Samba Share Install samba vi /etc/samba/smb.conf configure firewall NFS Modify /etc/exports start nfs & portmap verify config, & check mounts exportfs -v showmount -e localhost rpcinfo -p localhost service nfs reload Automount mkdir /net vi /etc/auto.master start services -- portmap, autofs FTP install vsftpd create incoming directory mkdir -p /var/ftp/incoming vi /etc/vsftpd/vsftpd.conf start vsftpd service vsftpd start Web proxy Install squid, and start the service vi /etc/squid service squid reload Configure browser to test SMTP Install sendmail, sendmail-cf, sendmail-doc modify /etc/mail/sendmail.mc m4 sendmail.mc > sendmail.cf (or make) service sendmail restart IMAP, IMAPS, and POP3 install dovecot vi /etc/dovcot.conf protocols = xxx service dovecot restart chkconfig dovecot on SSH /etc/ssh/ ~/.ssh/ DNS Install bind, bind-utils, and caching-nameserver vi /etc/named.conf To verify: named-checkconf named-checkzone example.com example.com.zone Check /etc/resolv.conf on client machines NTP /etc/ntp.conf ntpstat service ntpd restart Firewall /etc/sysconfig/iptables iptables -L iptables -F service iptables save service iptables restart chkconfig iptables on PAM /lib/security/ /etc/pam.d/ Configure Service Install RPM rpm -ivh servicename.rpm Modify Configuration and Firewall Start Service service servicename restart Set Service to Start on Reboot chkconfig servicename on