Serba-serbi Operating System

BASH - Delete empty lines using sed command under Linux / UNIX: $ sed -i '/^$/d' file

BASH - Convert Date Time: $ date="20181108101344z"; echo -e "date -d \"${date[@]:0:8} ${date[@]:8:2}:${date[@]:10:2}:${date[@]:12:3}+0 hours\" '+%c'" Output: Kam 08 Nov 2018 05:13:44  WIB

BASH - Convert TimeStamp to Date: $ date -d @1560009306 Output: Sab Jun  8 22:55:06 WIB 2019

BASH - Lowercase the word: $ echo "IVANHOE" | tr '[:upper:]' '[:lower:]' Output: ivanhoe

BASH - Uppercase the word: $ echo "ivanhoe" | tr '[:lower:]' '[:upper:]' Output: IVANHOE

BASH - Uppercase first character: foo=bar echo "${foo^}" Output: Bar

BASH - How to just input 'y' without having to press ENTER" Use -n1 with read to specify max number of input length to 1: $ read -n1 -p "Do you want to update the tv feed? [y/n/q] "

BASH - Double and triple substitution $ a="abc"; b="123"; abc123="ivanhoe"; eval echo "\${$a$b}" Output: ivanhoe

BASH - Capitalizing the first of a line (Uppercase): $ echo "the first word is not capitalized." | sed 's/.*/\u&/' The first word is not capitalized. OR $ echo "the first word is not capitalized." | sed 's/^./\u&/' The first word is not capitalized.

BASH - You can comment out multiple lines in BASH script: :<<'COMMENTOUT' KALIMAT INI TIDAK DIGUNAKAN ALIAS TIDAK AKTIF COMMENTOUT

BASH - sort a file in-place: $ sort -o file file

BASH - print lines 17-24 from a file, first using head to get the first 24 lines then tail to get the last 8: $ ifconfig | head -24 | tail -8

BASH - Extract the first 85 lines from a file: $ head -85 file.txt

BASH - Using Bash script to find line number of string in file: $ ifconfig | awk '/wlp2s0/{ print NR; exit}'

BASH - compare two floating point number: $ a=3.2; b=3.2; if (( $(echo "$b >= $a" | bc -l) )); then echo "b lebih besar dan sama dari a"; else echo "b lebih kecil dari a"; fi

BASH - Scale Math Calc: $ echo "scale=2;(1560010540 - 1560003310) / 3600" | bc

BASH - Convert Date to TimeStamp: $ date -d "$(date '+%Y-%m-%d %H:%M:%S')" +%s Output: 1560009306

BASH - How to change the title of the current terminal tab using only the command line: $ echo -en "\033]0;New terminal title\a" $ PROMPT_COMMAND='echo -en "\033]0;New terminal title\a"'

BASH - How do I get a colored bash?   Open ~/.bashrc in an editor Copy this and add it at the end of .bashrc file: PS1='\[\033[1;36m\]\u\[\033[1;31m\]@\[\033[1;32m\]\h:\[\033[1;35m\]\w\[\033[1;31m\]\$\[\033[0m\] ' Save the file and restart bashrc: $ source ~/.bashrc $ PS1='\[\033[1;36m\]\u\[\033[1;31m\]\$\[\033[0m\] '