Linux Ask!

List processes by memory usage

Mar 242008

List processes by memory usage

Answer:

To list all of your current system's running processes, and sort by memory usage, try

# ps -e -o pcpu,cpu,nice,state,cputime,args --sort pcpu | sed '/^ 0.0 /d'

    0 [aio/0]
    0 [ata/0]
    0 [ata_aux]
    0 [cqueue]
    0 [events/0]
    0 [kacpi_notify]
    0 [kacpid]
    0 [kblockd/0]
    0 [khelper]
    0 [kintegrityd/0]
.
.
.
29528 /usr/sbin/apache2 -k start
29536 /usr/sbin/apache2 -k start
29860 /usr/sbin/apache2 -k start
30320 /usr/sbin/apache2 -k start
32588 /usr/sbin/apache2 -k start

How do I check memory information in Linux?

Basic Linux No Responses »

Mar 212008

How do I check memory information in Linux?

Answer:

In Linux, you can check the memory information by using the command:

# cat /proc/meminfo

Search the history of commands you have executed

Commands No Responses »

Mar 182008

Search the history of commands you have executed

Answer:

You typed a lot of commands, and you want to search them, the simplest method is to press Ctrl+r

# [press Ctrl+r]

(reverse-i-search)`da': date

In the above example, I typed the characters "da" and the shell auto matched the command "date" for me - which I have typed in an earlier session.

What is the maximum length of a valid UTF-8 character?

Advanced Linux No Responses »

Mar 042008

What is the maximum length of a valid UTF-8 character?

Answer:

A valid UTF-8 character take up 1 to 4 bytes (and within each octet, only the first 128 US-ASCII characters is used, so it can compatible with legacy systems).

A subset of UTF-8 called UTF-8 Basic Multilingual Plane (BMP), which only takes 3 bytes and can represent most frequently used characters and is compatible with UTF-16/UCS-2.

Reference: http://en.wikipedia.org/wiki/UTF-8

Audible ping

Commands No Responses »

Mar 022008

Audible ping

Answer:

Sometimes you want to listen your machine pinging another machine (remote machine), especially you want to know when the remote machine is alive when you have issued a reboot.

It is easy with the ping command.

# ping -a google.com

Open your speaker to listen.

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