Goku Coding Experience: March 2020

Monday 30 March 2020

how to create virtual environment without conda?

python -m pip install --user virtualenv

cd to install location path of env

python -m virtualenv env

source env/bin/activate

libgflags.a(gflags.cc.o): relocation R_X86_64_32S make pycaffe

gflags is not compiled as a shared library by default; make sure it is compiled as a shared library:

cd gflags/build
cmake .. -DBUILD_SHARED_LIBS=ON
make -j32
sudo make -j32 install

After that glog compiles fine against gflags.

Wednesday 18 March 2020

how to know the full path of a process / process pid?

pwdx pid

e.g.:-

pwdx 30580

how to create a ssh shortcut

cd ~/.ssh

vim config

Host 123
HostName 192.168.1.123
User ninja

/usr/lib/libprotobuf.a: error adding symbols: Bad value

Monday 16 March 2020

How to calculate fps from elapsed time?

p/s: copy from https://stackoverflow.com/questions/43761004/fps-how-to-divide-count-by-time-function-to-determine-fps

Here is a very simple way to print your program's frame rate at each frame (no counter needed) :

import time

while True:
    start_time = time.time() # start time of the loop

    ########################
    # your fancy code here #
    ########################

    print("FPS: ", 1.0 / (time.time() - start_time)) # FPS = 1 / time to process loop

If you want the average frame rate over x seconds, you can do like so (counter needed) :

import time

start_time = time.time()
x = 1 # displays the frame rate every 1 second
counter = 0
while True:

    ########################
    # your fancy code here #
    ########################

    counter+=1
    if (time.time() - start_time) > x :
        print("FPS: ", counter / (time.time() - start_time))
        counter = 0
        start_time = time.time()

Hope it helps!

Wednesday 11 March 2020

cannot find -lboost_python3

cd /usr/lib/x86_64-linux-gpu

sudo ln -s libboost_python-py35.so libboost_python3.so

cannot find -lboost_python3

cd /usr/lib/x86_64-linux-gpu

sudo ln -s libboost_python-py35.so libboost_python3.so

Tuesday 10 March 2020

How to check system specifications in Ubuntu Server 16.04 with the CLI

p/s: copy from https://ourcodeworld.com/articles/read/768/how-to-check-system-specifications-in-ubuntu-server-16-04-with-the-cli

$sudo apt-get install hardinfo

or

1. Install lshw (HardWare LiSter for Linux)

lshw is a small tool to provide detailed information on the hardware configuration of the machine. It can report exact memory configuration, firmware version, mainboard configuration, CPU version and speed, cache configuration, bus speed, etc. on DMI-capable x86 or EFI (IA-64) systems and on some ARM and PowerPC machines (PowerMac G4 is known to work). The information can be output in plain text, XML or HTML. It currently supports DMI (x86 and EFI only), OpenFirmware device tree (PowerPC only), PCI/AGP, ISA PnP (x86), CPUID (x86), IDE/ATA/ATAPI, PCMCIA (only tested on x86), USB and SCSI.
To install this package on your ubuntu system, run the following command:

sudo apt-get install lshw

After the installation you will be able to list all the specifications of your server eitherin HTML format or plain text. For more information about this project, visit the official repository here.

2. Generate inline short specs list

The prefered way for almost every user of this tool, is a short list with the description and values of the components of our interest, namely the processor, RAM, storage capacity and network information. lshw allows you to see such description with the following command:

sudo lshw -short

That will generate an output similar to:

H/W path        Device     Class       Description
==================================================
                           system      VirtualBox
/0                         bus         VirtualBox
/0/0                       memory      128KiB BIOS
/0/1                       memory      1999MiB System memory
/0/2                       processor   Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz
/0/100                     bridge      440FX - 82441FX PMC [Natoma]
/0/100/1                   bridge      82371SB PIIX3 ISA [Natoma/Triton II]
/0/100/1.1                 storage     82371AB/EB/MB PIIX4 IDE
/0/100/2                   display     VirtualBox Graphics Adapter
/0/100/3        eth0       network     82540EM Gigabit Ethernet Controller
/0/100/4                   generic     VirtualBox Guest Service
/0/100/5                   multimedia  82801AA AC'97 Audio Controller
/0/100/7                   bridge      82371AB/EB/MB PIIX4 ACPI
/0/100/8        eth1       network     82540EM Gigabit Ethernet Controller
/0/100/d                   storage     82801HM/HEM (ICH8M/ICH8M-E) SATA Controll
/0/3            scsi2      storage
/0/3/0.0.0      /dev/sda   disk        68GB VBOX HARDDISK
/0/3/0.0.0/1    /dev/sda1  volume      487MiB Linux filesystem partition
/0/3/0.0.0/2    /dev/sda2  volume      63GiB Extended partition
/0/3/0.0.0/2/5  /dev/sda5  volume      63GiB Linux LVM Physical Volume partition

3. Generate general specs list as HTML

If for you isn't enough a short description on the CLI, lshw is able to generate an HTML based report with the a detailed description of all the components of your ubuntu based server, just set the output format to html and pipe its content into a HTML file:

sudo lshw -html > server_specs.html

The content of the server_specs.html file will then look something like:

This option is pretty useful when you have to provide a detailed description for someone that doesn't have access to the server. You can simply print the file or send it to someone else.

4. Generate specific component description

If you want detailed description about a specific component of your system, simply filter the output specifyng the component that you want with the -c argument:

sudo lshw -C [component name]

For example: