Thejazeto Lhousa

Common Dev Tooling Quickref

Posted on Jul 28, 2024

Some useful commands for some common dev tools. Assumption is that the reader is already familiar with the tools.

Vim

  • Replace all instances:
%s/orignal/replacement/g

:w !sudo tee %
  • See filename
ctrl + g
  • Delete lines matching pattern
:g/<pattern>/d` (remove /d if only to show patterns)
  • Highlight multiple patterns
:/\vpattern1|pattern2|…
  • Go to bottom of match
GN
  • Got to top of match
ggn
  • Set and unset line numbers and relative numbers inside vim
:set nu rnu
:set nonu nornu
  • Show x out of y count for searches
:set shormess-=S

Terminal

  • save output to file/code
$ <command> 2>&1 | tee file.txt
  • dig, whatis, whois, whoami
  • TOTRY: tldr, exa, btop, lsd, duff
  • show process tree
$ pstree -p (linux only)
  • run command in background
$ nohup <other command> &
$ fg #to bring it back
$ jobs #to list process in background
  • switch user
$ su - <username>

$ sudo curl -s https://cht.sh/:cht.sh > [cht.sh](http://cht.sh/)
$ sudo mv [cht.sh](http://cht.sh/) /usr/local/bin
$ sudo chmod +x /usr/local/bin/cht.sh
  • set up cronjob
crontab -e
#<schedule_pattern> <path_to_executable_script> 
#http://crontab.guru/
  • ssh with agent forwarding
ssh -A <host>
#or just modify the .ssh/config file with `ForwardAgent=yes`
  • Keeping keys in memory
$ eval `ssh-agent`
$ ssh-add <*secret_keys*>
$ ssh-add --apple-use-keychain .ssh/id_rsa #for mac
$ `ssh-add -L #list keys added
  • Remove keys for a host
$ ssh-keygen -R <host>
  • Resolving “REMOTE HOST IDENTIFICATION HAS CHANGED!” warning when ssh-ing
$ ssh -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null <host>
  • access a website from terminal
$ curl -i <url>
  • get active ssh sessions
$ who
  • get all python versions
$ ls -ls /usr/bin/python* | awk ‘{ print $10 }’
  • get IP of laptop
$ ipconfig getifaddr en0
  • get environment variables
$ env #current session level
$ set #system wide level
  • decompress gzipped files (.gz)
$ gzip -d <file>
  • extract tar file
$ tar -xf <file>
  • get md5 diffs
$ md5sum <files...>
  • get permissions of current user
$ id
$ sudo -l
  • copy all modified git files into a folder
$ git status -s | grep M | awk '{print $2}' | xargs -I {} cp --parents {} diff/
  • find all files in directory tree and move them
$ find . -type f | xargs -I {} cp {} u18/
  • Find filename pattern
$ find . -name "regex_pattern"
  • Find directory
$ find . -type d -name "regex_pattern"
  • Change default shell to zsh
$ chsh -s $(which zsh)

$ export LC_ALL=C.UTF-8
  • Debug core dumps
$ gdb program_file core_file
  • View core size limit
ulimit -c
  • Grep around a pattern
$ grep -B 4 -A 4 foo_pattern README.txt` #4 lines Before and After pattern
$ grep -C 4 pattern #simpler

$ grep "^pattern" #should start with pattern
$ grep "pattern$" #should end with pattern
$ grep "..ttern" #matches any two chars followed by pattern eg: pattern, sottern, kettern
$ grep "p[aou]ttern" #pattern should match one of the chars in brackets
$ grep 'pattern1\|pattern2' #OR condition
  • Grep header row as well
$ <command> | grep -E 'column|pattern'
  • Live grep
$ tail -f <file> | grep <pattern>
  • Number of lines in a gzipped file
$ zcat <file> | wc -l
  • To know if your machine is virtual machine or bare-metal
$ virt-what #returns nothing if bare-metal
  • Block device info
$ blkid or lsblk
  • View boot logs
$ journalctl -b -1
  • Get time in epoch
$ date +%s
  • Change timezone
$ sudo timedatectl set-timezone UTC
  • Sort lines in a file
$ sort -o file file
  • View kernel configs
$ zcat /proc/config.gz | grep CONFIG_FRAME_WARN
  • Dedupe hourly log filenames to get unique filename in directory:
$ ls | sed 's/-[0-9]\{10\}\(\.tar\)\?\.\(gz\|zst\)//' | sort | uniq
# eg: hello.log-2024022115.gz ⇒ hello.log
  • Create symlink
$ ln -s <source> <symlink>

Tmux

  • Swap panes
: switch-pane -s<pane#> -t<pane#>
  • Sync all panes (set and unset)
: setw synchronize-pane

Git

  • Auto add upstream
$ git config --global --add --bool push.autoSetupRemote true
  • Show commit by a sha
$ git show d41ed690882c2345a249e17a1908232f92163a
  • Rename branch
$ git branch -m old new
  • Create branch from source and new
$ git checkout -b new old
  • Diff file between two branch
$ git diff branch1 branch2 -- filename
  • Show commits from one author
$ git log --author='email'
  • Show which branch contains commit
$ git branch --contains 086062f79c5 #add -r to search remote
  • Show branch matching name
$ git branch -rl ‘*pattern*’
  • Show changes by commit
$ git diff commit~ commit
  • Push a branch without checking out
$ git push --set-upstream origin <branch>
  • Show commits matching string
$ git log --grep "<pattern>"
  • Replace local branch with remote (first checkout )
$ git reset --hard origin/<branch>
  • Sync files by not copying unnecessarily
rsync -avzhe ssh --checksum user@machine1:/remote_source/ /local_destination/ | grep -q 'Number of files transferred: 0'

Other useful resources