Jump to Navigation


245 - du command

The du command is used to summarize disk usage of each file in a file system, recursively for directories.

# du -s /var/log/* | sort -nr | head -5

# du -s ./* | sort -nr | head -5



238 - Navisphere diagnosis on SP

< EMC Storage Management Soft >

  1. Log into Navisphere GUI.
  2. Right click on SPA. Choose SPCollect. This can take up to 5 minutes to complete even though you have already received the success notification.
  3. Right click on SPA. Choose “File Transfer Manager”.
  4. Sort files by date.
  5. Look for the file that is similar in format to SPA__APM000xxxxxxxx_xxxxxx_date_time_data.zip with today’s date.
  6. Transfer this file to your desktop.
  7. Repeat steps for SPB, and then reply to this email with the 2 zip files attached.

234 - Build packages from sorce codes

The rpmbuild command is used to build RPM package. The syntax for rpmbuild is :

# rpmbuild -[b|t]stage [build-option] spec-file ....

Specify -b to build a package directly from a spec file, or -t to open a tarred gzipped file and use its spec file.

1. You need to have the rpmbuild package in Linux server.


229 - 7zip

7-Zip is an amazing compression program. Compression ratio results are very dependent upon the data used for the tests. Usually,
7-Zip compresses to 7z format 30-70% better than to zip format. And 7-Zip compresses to zip format 2-10% better than most of
other zip compatible programs.

1. You can search rpm if you want

 URL- http://rpm.pbone.net/

2. Copy the link and use it to rpm comand with "-ivh"


222 - Manage file attributes

A file attribute is metadata that describes or is associated with a computer file.

1. chattr - change file attributes on a Linux second extended file syst

chattr [ -RV ] [ -v version ] [ mode ] files...

# chattr -a myfile

-----a------- myfile

# chattr +i myfile

2. lsattr - list file attributes on a Linux second extended file system


216 - How to use mpstat

The mpstat command writes to standard output activities for each available processor, processor 0 being the first one. Global average activities
among all processors are also reported. The mpstat command can be used both on SMP and UP machines, but in the latter, only global average
activities will be printed. If no activity has been selected, then the default report is the CPU utilization report.

mpstat [ -P { cpu | ALL } ] [ -V ] [ interval [ count ] ]

-P : cpu number(0, 1, ...) or ALL
-V : Version Number


215 - nmap

nmap is a powerfull scanner available in Unix/Linux system. It’s very usefull for network exploration and security auditing.
It was designed to rapidly scan large networks, although it works fine againts single hosts.

Usage: nmap [Scan Type(s)] [Options] {target specification}


213 - Editor on Linux

Some Linux Based OS does not comes with your favorites editor. And maybe in some case the default editor is not the one you are used to.
For example, you need to update the crontab:

# crontab -e

pico or nano, (for example) opens up.

If you personally have a preference for VI and you wanted to change it to the editor you are used to.

To update the default editor you simply need to execute:


210 - Top-Level Domain (TLD)

A root name server is a name server for the Domain Name System's root zone. It directly answers requests for records in the root zone
and answers other requests returning a list of the designated authoritative name servers for the appropriate top-level domain (TLD).

The newest DNS root zoon on.

# dig @a.root-servers.net ns


204 - Top 5 large files in a directory

If you want to figure out large files in a specific directory.

# du -s /var/log/* | sort -nr | head -5

There are a lot of files in a current directory and want to figure out.

# du -s ./* | sort -nr | head -5


  • du

 This command is used to summarize disk usage of each file in a file system, recursively for directories.



Subscribe to RSS - command

Main menu 2

by Dr. Radut