Collection of useful Linux commands in daily work

useful linux cmds.md

List some useful Linux commands here.

copy directory content recursively:

cp -a <src>/. <dst>/

• -a option is an improved recursive option, that preserve all file attributes, and also preserve symlinks.

• . at end of the source path is a specific cp syntax that allow to copy all files and folders, included hidden ones.

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command line - How can I copy the contents of a folder to another folder in a different directory using terminal? - Ask Ubuntu

• https://askubuntu.com/questions/86822/how-can-i-copy-the-contents-of-a-folder-to-another-folder-in-a-different-directo

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Another solution:

cp -R <src>/* <dst>

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• How To Copy Directory on Linux – devconnected
  • https://devconnected.com/how-to-copy-directory-on-linux/

get ip from domain:

dig +short xxx.yyy.com

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• Linux command to translate DomainName to IP - Stack Overflow
  • https://stackoverflow.com/a/3963098/

Get head of http(s) response from url:

curl -I <url>

Check disk space usage:

ncdu --exclude ~/.snapshot ~

Find text or string in all files:

grep -rnw '/path/to/somewhere/' -e 'pattern'

• -r or -R: recursive
• -n: show line number
• -w: match the whole word
• -l (lower-case L): just show the file name of matching files
• -e: pattern used during the search

Example:

grep --include=\*.{py,sh} -rnw './script' -e 'threshold'

References:

• How to find all files containing specific text (string) on Linux? - Stack Overflow
  • https://stackoverflow.com/questions/16956810/how-to-find-all-files-containing-specific-text-string-on-linux
• grep Man Page - Linux - SS64.com
  • https://ss64.com/bash/grep.html

List file structure by tree:

ls -R | grep ":$" | sed -e 's/:$//' -e 's/[^-][^\/]*\//--/g' -e 's/^/   /' -e 's/-/|/'

also contain files:

find . | sed -e "s/[^-][^\/]*\//  |/g" -e "s/|\([^ ]\)/|-\1/"

Add alias to ~./.bashrc:

alias lr=ls -R | grep ":$" | sed -e 's/:$//' -e 's/[^-][^\/]*\//--/g' -e 's/^/   /' -e 's/-/|/'
# use `lr` instead of `lt` to avoid default settings `alias lt='ls -lt'`
alias lf=find . | sed -e "s/[^-][^\/]*\//  |/g" -e "s/|\([^ ]\)/|-\1/"

References:

• Linux command to print directory structure in the form of a tree - Stack Overflow
  • https://stackoverflow.com/questions/3455625/linux-command-to-print-directory-structure-in-the-form-of-a-tree

nvidia-smi -q -x | grep pid | sed -e 's/<pid>//g' -e 's/<\/pid>//g' -e 's/^[[:space:]]*//'`

References:

• cuda - How do I customize nvidia-smi 's output to show PID username? - Stack Overflow
  • https://stackoverflow.com/questions/50264491/how-do-i-customize-nvidia-smi-s-output-to-show-pid-username

List process run on port 28888:

lsof -i:28888

Kill a process run on port 28888:

kill $(lsof -i:28888 | awk 'NR>1 {print $2}')