DevOps' tips & tricks for GNU/Linux developers

DevOps' tips & tricks for GNU/Linux developers

1. Q: Ansi terminal for Windows
   A:
   1. download and install wsltty
   2. launch your program under mintty: mintty.exe program.exe
   
   
2. Q: globally replace include path details in whole Golang project using sed
   A: 

   find . -name '*.go' -type f -execdir sed -i \
   "s#github.com/fiorix/go-smpp#github.com/Zensey/go-smpp#" \
   '{}' \;
   

   
   Changes from / to (example):
   include "github.com/fiorix/go-smpp"
   include "github.com/Zensey/go-smpp"
   
   
3. Q: simulate client disconnect on GNU/Linux server
   A:
   # iptables -A INPUT -s 11.22.33.44 -j DROP; iptables -D INPUT -s 11.22.33.44 -j DROP
   where 11.22.33.44 is client's IP
   
   
4. Q: How to set udev rule to grant access for usb termo-printer (for example Godex) ?
   A:
   Create and edit file /etc/udev/rules.d/99-printers.rules
   Set ATTRS{idVendor} and ATTRS{idProduct} to proper vendor/product id of your printer:
   

   ACTION=="add", SUBSYSTEM=="usb", ENV{DEVTYPE}=="usb_device", ATTRS{idVendor}=="195f", ATTRS{idProduct}=="0001", ENV{ID_USB_INTERFACES}=="*:0701??:*", MODE="0666"
   

   
   
5. Q: Git. merge changes from given tag
   A:
   git fetch --tags origin
   git merge tag_name
   
   
6. Q: Git. Push a tag to origin
   A:
   After creating a tag in local branch do git push origin <tag_name> for  ex. git push origin v1.3.4
7. Q: Git. merge changes from given tag
   A:
   git describe --tags --always
   
   
8. Q: Esptool. Dump ESP's ROM (for 1 megabyte)
   A:
   ./esptool.py --port /dev/ttyUSB0 read_flash 0x00000 0x100000 ./dump_1.bin
   
   
9. Q: Esptool. Erase ESP's ROM
   A:
   ./esptool.py --port /dev/ttyUSB0 erase_flash
   
   
10. Q: Redmine. Get info about ticket using REST API
    A:
    wget https://Server/issues/12345.json?include=journals
    
    
11. Q: Batch conversion mp4 -> mp3
    A:
    find -name "*.mp4" -type f -execdir ffmpeg -i '{}' -f mp3 '{}'.mp3 \;
    
    
12. Q: How to share a folder using HTTP, for ex. to transfer files from PC to mobile ?
    A:
    
    Download webserver.go from https://gist.github.com/alexisrobert/982674
    Run:
    go run webserver.go
    
    
13. Q: How to capture audio of conversation in Skype / Voip or any other program
    A:
    Use audio-recorder. To install it on Ubuntu use repository ppa:audio-recorder/ppa.
    
    
14. Q: Test local syslog logging
    A:
    logger -t topic -p local0.debug TestMsg
    
    
15. Q: Git. Spawning a branch from an empty state, before any commit has been made
    A:
    git checkout --orphan my_namespace/new_project/master
    
    
16. Q: Git. How to merge the last commit with a previous one
    A:
    git reset HEAD~1
    git commit --amend
    
17. Q: Git. How to merge the last commit with a previous one
    A:
    git reset HEAD~1
    git commit --amend