Useful Linux Commands

[supereagle]

Category

• How to rsync
• Install software by rpm
• Uninstall softwares without its dependency

Reference

• Linux Command Reference
• Hong Kong Linux User Group
• perf Examples

[supereagle]

How to rsync

rsync -havAEHXi -n --numeric-ids --stats --progress src_dir/ dst_ip:/dst_dir/

• -n：测试需要同步的内容(不加，直接进行同步)
• --exclude： 排除某些目录

[supereagle]

Install software by rpm

 # rpm -ivh netplugin-1-0.1.20160413.17.x86_64.rpm --force --nodeps

• --nodeps：Don't verify package dependencies.
• --force：Short hand for --replacepkgs --replacefiles. Install by force when there are conflicts.

# rpm -ivh netplugin-1-0.1.20160413.17.x86_64.rpm
error: Failed dependencies:
    docker is needed by netplugin-1-0.1.20160413.17.x86_64

rpm -ivh netplugin-1-0.1.20160413.17.x86_64.rpm --nodeps
Preparing...                          ################################# [100%]
    file /etc/sysconfig/netplugin/netplugin from install of netplugin-1-0.1.20160413.17.x86_64 conflicts with file from package netplugin-1-0.1.20160413.15.x86_64
    file /usr/local/bin/netplugin from install of netplugin-1-0.1.20160413.17.x86_64 conflicts with file from package netplugin-1-0.1.20160413.15.x86_64
    file /etc/sysconfig/netplugin/netmaster from install of netplugin-1-0.1.20160413.17.x86_64 conflicts with file from package netplugin-1-0.1.20160413.15.x86_64
    file /usr/local/bin/netmaster from install of netplugin-1-0.1.20160413.17.x86_64 conflicts with file from package netplugin-1-0.1.20160413.15.x86_64
    file /usr/lib/systemd/system/netmaster.service from install of netplugin-1-0.1.20160413.17.x86_64 conflicts with file from package netplugin-1-0.1.20160413.15.x86_64
    file /usr/lib/systemd/system/netplugin.service from install of netplugin-1-0.1.20160413.17.x86_64 conflicts with file from package netplugin-1-0.1.20160413.15.x86_64
    file /usr/local/bin/netctl from install of netplugin-1-0.1.20160413.17.x86_64 conflicts with file from package netplugin-1-0.1.20160413.15.x86_64

[supereagle]

Software dependencies

Check the dependencies of the software

# rpm -qRp docker-engine-1.13.0-1.el7.centos.x86_64.rpm
warning: docker-engine-1.13.0-1.el7.centos.x86_64.rpm: Header V4 RSA/SHA512 Signature, key ID 2c52609d: NOKEY
/bin/sh
/bin/sh
/bin/sh
/bin/sh
device-mapper-libs >= 1.02.90-1
docker-engine-selinux >= 1.13.0-1.el7.centos
iptables
libc.so.6()(64bit)
libc.so.6(GLIBC_2.14)(64bit)
libc.so.6(GLIBC_2.17)(64bit)
libc.so.6(GLIBC_2.2.5)(64bit)
libc.so.6(GLIBC_2.4)(64bit)
libc.so.6(GLIBC_2.9)(64bit)
libcgroup
libdevmapper.so.1.02()(64bit)
libdevmapper.so.1.02(Base)(64bit)
libdevmapper.so.1.02(DM_1_02_97)(64bit)
libdl.so.2()(64bit)
libltdl.so.7()(64bit)
libpthread.so.0()(64bit)
libpthread.so.0(GLIBC_2.2.5)(64bit)
libpthread.so.0(GLIBC_2.3.2)(64bit)
libseccomp.so.2()(64bit)
libsystemd.so.0()(64bit)
libsystemd.so.0(LIBSYSTEMD_209)(64bit)
rpmlib(CompressedFileNames) <= 3.0.4-1
rpmlib(FileDigests) <= 4.6.0-1
rpmlib(PayloadFilesHavePrefix) <= 4.0-1
rtld(GNU_HASH)
selinux-policy >= 3.13.1-23
systemd-units
tar
xz
rpmlib(PayloadIsXz) <= 5.2-1

Uninstall softwares without its dependency

# rpm -e --nodeps docker

[supereagle]

Get network ip

# ifconfig eth0
# ip addr show eth0

[supereagle]

Catch network packages

tcpdump -i eth0 tcp

The network protocol can be tcp, udp, arp and vrrp.

[supereagle]

Check the resources used by process

Check the port used by process

lsof -i :8080

Check the file used by process

# lsof /var/log/messages
COMMAND  PID USER   FD   TYPE DEVICE SIZE/OFF     NODE NAME
rsyslogd 573 root    4w   REG  253,1   987941 10197674 /var/log/messages
# ps -ef | grep 573
root       573     1  0 Feb28 ?        01:08:57 /usr/sbin/rsyslogd -n
root     15880 25698  0 18:12 pts/0    00:00:00 grep --color=auto 573

[supereagle]

Check the IO status

# iostat -x 1
avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.00    0.00    0.00    0.00    0.00  100.00

Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s avgrq-sz avgqu-sz   await r_await w_await  svctm  %util
vda               0.00     0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00    0.00    0.00   0.00   0.00
vdb               0.00     0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00    0.00    0.00   0.00   0.00
vdc               0.00     0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00    0.00    0.00   0.00   0.00
dm-0              0.00     0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00    0.00    0.00   0.00   0.00
dm-1              0.00     0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00    0.00    0.00   0.00   0.00
dm-2              0.00     0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00    0.00    0.00   0.00   0.00
dm-4              0.00     0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00    0.00    0.00   0.00   0.00
dm-3              0.00     0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00    0.00    0.00   0.00   0.00

The IO has errors when: iowait > 50%, or util ~ 100%.

[supereagle]

Debug kernel error

# dmesg

[supereagle]

Disable IPv6

1. Check current config cat /proc/sys/net/ipv6/conf/all/disable_ipv6
   • 1: Disabled
   • 0: Enabled
2. Add net.ipv6.conf.all.disable_ipv6 = 1 into /etc/sysctl.conf
3. Reload the config: sysctl -p

[supereagle]

Sync files between Linux/Unix and local Windows

• Sync files from Linux/Unix to Windows

  sz filename

• Sync files from Windows to Linux/Unix

  rz -e

  Need to install lrzsz on the Linux/Unix by yum install -y lrzsz.

[supereagle]

Network performance test

# Start server on the default port
$ iperf3 -s

# Run a 30 second tests, giving results every 1 second
$ iperf3 -c ${remotehost} -i 1 -t 30