Category: linux

rocky linux enable time sync – ntp timedatectl

[root@lp-knode-1 ~]# date
Tue Mar  4 19:32:46 IST 2025

[root@lp-knode-1 ~]# timedatectl
               Local time: Tue 2025-03-04 19:33:01 IST
           Universal time: Tue 2025-03-04 14:03:01 UTC
                 RTC time: Tue 2025-03-04 14:27:56
                Time zone: Asia/Kolkata (IST, +0530)
System clock synchronized: no
              NTP service: inactive
          RTC in local TZ: no


[root@lp-knode-1 ~]# timedatectl set-ntp on
[root@lp-knode-1 ~]# timedatectl status
               Local time: Tue 2025-03-04 20:00:13 IST
           Universal time: Tue 2025-03-04 14:30:13 UTC
                 RTC time: Tue 2025-03-04 14:30:13
                Time zone: Asia/Kolkata (IST, +0530)
System clock synchronized: yes
              NTP service: active
          RTC in local TZ: no

[root@lp-knode-1 ~]# date
Tue Mar  4 20:00:17 IST 2025

Run ollama on linux

Ollama it has similar pattern as docker.

  • Download 
curl -L https://ollama.com/download/ollama-linux-amd64.tgz -o ollama-linux-amd64.tgz
sudo tar -C /usr -xzf ollama-linux-amd64.tgz

ollama serve

# OR host on different ip
OLLAMA_HOST=192.168.29.13:11435 ollama serve

ollama -v

#check graphics card
nvidia-smi


#port http://127.0.0.1:11434/

###Podman/Docker - https://ollama.com/blog/ollama-is-now-available-as-an-official-docker-image

podman run -d --gpus=all --device nvidia.com/gpu=all --security-opt=label=disable -v ollama:/root/.ollama -p 11434:11434  ollama/ollama
  • Run
user@home:~$ ollama list
NAME               ID              SIZE      MODIFIED     
gemma2:latest      ff02c3702f32    5.4 GB    11 hours ago    
llama3.2:latest    a80c4f17acd5    2.0 GB    12 hours ago 

user@home:~$ ollama run llama3.2
>>> hola
Hola! ¿En qué puedo ayudarte hoy?

>>> hey
What's up? Want to chat about something in particular or just shoot the breeze?

podman run -d -p 3000:8080 --gpus all --device nvidia.com/gpu=all --security-opt=label=disable -e OLLAMA_BASE_URL=http://192.168.29.13:11434 -e WEBUI_AUTH=False -v open-webui:/app/backend/data --name open-webui ghcr.io/open-webui/open-webui:main

https://github.com/ollama/ollama/blob/main/docs/linux.md

for podman GPU access cdi- https://docs.nvidia.com/datacenter/cloud-native/container-toolkit/latest/cdi-support.html

https://docs.nvidia.com/datacenter/cloud-native/container-toolkit/latest/cdi-support.html

docker-compose-web.yml

services:
  open-webui:
    image: ghcr.io/open-webui/open-webui:main
    deploy:
      resources:
        reservations:
          devices:
            - driver: nvidia
              count: all
              capabilities: [gpu]
    restart: always
    container_name: open-webui
    environment:
      - OLLAMA_BASE_URL=http://192.168.29.142:11434
      - WEBUI_AUTH=False
    volumes:
      - open-webui:/app/backend/data
    ports:
      - 3000:8080
volumes:
  open-webui:
  • Verify nvidia driver 
docker run --rm  --gpus all ubuntu nvidia-smi
user@home:~$ cat /proc/driver/nvidia/version
NVRM version: NVIDIA UNIX x86_64 Kernel Module  550.120  Fri Sep 13 10:10:01 UTC 2024

apt install nvidia-utils-550

nvtop

encrypt files on linux system

Encyrtion tool:

UI:

Create volume > cryfs > Vloume path(This is where excerpted data will be stored) > Volume name(eg. test-cryfs) > Password.Key > Create

df -hT 

#view mount directory. Copy your data to mount directory


[home@home ~]$ df -hT
Filesystem                                Type        Size  Used Avail Use% Mounted on
devtmpfs                                  devtmpfs     32G     0   32G   0% /dev
tmpfs                                     tmpfs        32G  345M   31G   2% /dev/shm
tmpfs                                     tmpfs        13G  2.1M   13G   1% /run
/dev/mapper/fedora_localhost--live-root00 ext4        184G  174G  1.8G  99% /
tmpfs                                     tmpfs        32G   32M   32G   1% /tmp
/dev/nvme0n1p2                            ext4        974M  210M  698M  24% /boot
/dev/nvme0n1p1                            vfat        599M   14M  585M   3% /boot/efi
tmpfs                                     tmpfs       6.3G  188K  6.3G   1% /run/user/1000
cryfs@/home/home/cryfs-test               fuse.cryfs  1.8G   32K  1.8G   1% /home/home/.SiriKali/cryfs-test

Options = Select algo for encryption

Onedrive client: https://github.com/abraunegg/onedrive/

xargs understanding – linux

xargs pass the output(stdout) of first command to second command as argument. 

ls | xargs rm -f

This will remove all file listed by ls command

  • To understand properly what xargs is doing. use -p flag. It’s like dry-run.
[root@lp-k8control-1 xargs]# ls
test  test2  test3
[root@lp-k8control-1 xargs]# ls | xargs -p rm -f
rm -f test test2 test3 ?...

flag -n1 = one at a time

[root@lp-k8control-1 xargs]# ls | xargs -p -n1 rm -f
rm -f test ?...

flag -I % = run multiple command

[root@lp-k8control-1 xargs]# ls | xargs -p -n1 -I % /bin/bash -c 'ls %; ll %  '
/bin/bash -c ls test; ll test   ?...y
test

More : https://flaviocopes.com/linux-command-xargs/

Tmux , Screen, Nohup, – Run command in background

Why?
– Run process in background
– Run database backup in background

Tmux:

#List
tmux ls

#Start session
tmux new -s mysession

#Reconnect  
tmux a -t session_name

#Disconnect
ctrl + b + D


#Reconnect to 0 session
tmux a -t 0

More : https://tmuxcheatsheet.com

Screen :

#List
screen -ls

#Named session
screen -A -m -d -S session_name command

#Reconnect to named session
screen -r session_name 

#Disconnect
CTRL + a + d

https://gist.github.com/jctosta/af918e1618682638aa82

Nohup:

Nohup command &

It’s create nohup.out file in same directory with all command logs

https://www.thegeekdiary.com/nohup-command-examples-runs-a-command-that-keeps-running-after-you-log-out/

Jobs:

jobs
fg
bg

https://tldp.org/LDP/abs/html/x9644.html

Strings command in linux

strings /lib64/libc.so.6 |grep GLIBC

strings /bin/ls


Usage: strings [option(s)] [file(s)]
 Display printable strings in [file(s)] (stdin by default)
 The options are:
  -a - --all                Scan the entire file, not just the data section [default]
  -d --data                 Only scan the data sections in the file
  -f --print-file-name      Print the name of the file before each string
  -n --bytes=[number]       Locate & print any NUL-terminated sequence of at
  -<number>                   least [number] characters (default 4).
  -t --radix={o,d,x}        Print the location of the string in base 8, 10 or 16
  -w --include-all-whitespace Include all whitespace as valid string characters
  -o                        An alias for --radix=o
  -T --target=<BFDNAME>     Specify the binary file format
  -e --encoding={s,S,b,l,B,L} Select character size and endianness:
                            s = 7-bit, S = 8-bit, {b,l} = 16-bit, {B,L} = 32-bit
  -s --output-separator=<string> String used to separate strings in output.
  @<file>                   Read options from <file>
  -h --help                 Display this information
  -v -V --version           Print the program's version number
strings: supported targets: elf64-x86-64 elf32-i386 elf32-iamcu elf32-x86-64 a.out-i386-linux pei-i386 pei-x86-64 elf64-l1om elf64-k1om elf64-little elf64-big elf32-little elf32-big pe-x86-64 pe-bigobj-x86-64 pe-i386 plugin srec symbolsrec verilog tekhex binary ihex

connect to wifi using terminal in ubuntu

1.Create file and add wifi name and creds (vi /etc/wpa_supplicant.conf)

network={
    ssid="ssid_name"
    psk="password"
}

2.Connect

sudo wpa_supplicant -B -i wlan0 -c /etc/wpa_supplicant.conf -D wext
sudo dhclient wlan0

More : https://askubuntu.com/questions/138472/how-do-i-connect-to-a-wpa-wifi-network-using-the-command-line

https://askubuntu.com/questions/294257/connect-to-wifi-network-through-ubuntu-terminal