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os:linux:index.html



Linux

Commands

Linux Commands Cheat Sheet popular
bash
OpenSSL popular Check SSL Certificate Expiration Date :
openssl s_client -connect example.com:443 </dev/null 2>/dev/null|openssl x509 -text|grep -E "Not|Issuer:|sha"


Configuration

ssh popular Create Key Pair : ssh-keygen -t rsa -C "comment"
- How to use ProxyCommand with ssh
- ssh portfoward
X11 Forwarding
sudo /etc/sudoers
su /etc/pam.d/su
SELinux /etc/selinux/config
Check Command : getenforce
ntp /etc/ntp.conf
/etc/sysconfig/ntpd
ntpdate -b -u IPADDRESS
cron /var/spool/cron/USER
/etc/cron.d/FILE
snmp
LDAP
PAM
iptables


Log

Syslog

syslogd (RHEL5/centos5)
rsyslog (RHEL6,7/centos6,7)
journald (RHE7/centos7)
syslog-ng

Log Rotate

logrotate /etc/logrotate.conf

Note

International Configuration

LANG /etc/sysconfig/i18n
TimeZone /etc/localtime
/etc/sysconfig/clock
keyboard /etc/sysconfig/keyboard

Note


Install/Software

tftp Configuration : /etc/xinetd.d/tftp
Check : tftp IPADDR
pxe (preboot execution environment)
kickstart
yum popular
RHN (After RHEL5) LANG=C rhn_register --nox --proxy=http://192.168.0.10:9999


Network

Interface Configuration /etc/sysconfig/network-scripts/ifcfg-* (RHEL/CentOS)
/etc/network/interfaces (Debian/Ubuntu)
Bonding /etc/sysconfig/network-scripts/ifcfg-bondX
Alias
Negotiation Check : ethtool eth0
ETHTOOL_OPTS=“autoneg on speed 1000 duplex full”
Routing /etc/sysconfig/static-routes (RHEL/CentOS)
/etc/network/if-up.d/static-routes (Debian/Ubuntu)
Physical NICs Info
Network Driver ethtool -i eth0 ← Check NIC Driver
udev rules /etc/udev/rules.d/xx-xxxxxxx.rules
VLAN
Bridge
TOE
(TCP Offload Engine)

Note

Disk

NFS /etc/exports
HBA (WWN, Driver) systool -c fc_host -v |grep port_name
/opt/hp/hp_fibreutils/adapter_info ← HPE ProLiant Server
Scanning Storage /opt/hp/hp_fibreutils/hp_rescan -a ← HPE ProLiant
Basic Disk Operation parted or fdisk → mkfs → mount
multipath /etc/multipath.conf
multipath -ll → parted or fdisk → mkfs → mount
LVM multipath -ll → parted or fdisk → pvcreate → vgcreate → lvcreate → mkfs → mount
iSCSI


Performance

CPU The Number of Sockets : cat /proc/cpuinfo | grep "physical id" |sort | uniq | wc -l
The Number of Cores per Socket : cat /proc/cpuinfo | grep "cpu cores" |uniq
Memory
Swap
Loadaverage
Network


Kernel

Kernel Parameter sysctl -a ← check
/etc/sysctl.conf
User Resource ulimit -a ← check
/etc/security/limits.conf

Note




os/linux/index.html.txt · Last modified: 2017/07/07 by admin