# List all available shells in macOS X cat /etc/shells # To see which shell you’re running. echo $0 echo $BASH_VERSION echo $ZSH_VERSION # To change to bash shell. chsh -s /bin/bash # To change to zsh shell. chsh -s /bin/zsh

hw='Hello, World!' echo "$hw" # output of a command first_line=$(head -1 version.txt) echo "$first_line"

num='01234567' echo "${num:0:3}" # 012

hw='hello, world!' echo "${hw^}" # Hello, world! echo "${hw^^}" # HELLO, WORLD! hw='Hello, World!' echo "${hw,}" # hello, World! echo "${hw,,}" # hello, world!

majorVersion=$(echo "1.2.3" | cut -d "." -f 1) minorVersion=$(echo "1.2.3" | cut -d "." -f 2) buildNumber=$(echo "1.2.3" | cut -d "." -f 3) echo "${majorVersion} ${minorVersion} ${buildNumber}" buildNumber=$(echo "$(($buildNumber + 1))") echo "${majorVersion} ${minorVersion} ${buildNumber}" newPackageVersion=$majorVersion.$minorVersion.$buildNumber

hw='hello, world!' echo "${(U)hw}" echo "${hw:u}" hw='Hello, World!' echo "${(L)hw}" echo "${hw:l}" # hello, world!

read name echo "Hello, $name" 

history -1 -100

echo \# 5. Number Generation > Number\ Generation.md echo \# 6. Fibonacci Series > Fibonacci\ Series.md echo \# 7. Combinatorics > Combinatorics.md echo \# 8. Dynamic Programming > Dynamic\ Programming.md echo \# 9. Greedy > Greedy.md echo \# 10. Algorithm > Algorithm.md echo \# 11. Number Theory > Number\ Theory.md echo \# 12. Numerical Methods > Numerical\ Methods.md echo \# 13. Basics of Numbers > Basics\ of\ Numbers.md echo \# 14. Java > Java.md echo \# 15. Computational Geometry > Computational\ Geometry.md echo \# 16. Math > Math.md echo \# 17. Physics > Physics.md echo \# 18. ASCII Table > ASCII\ Table.md

for i in {15..50}; do mkdir "$i. " done

declare -a array=("Number Generation" "Fibonacci Series" "Combinatorics" "Algorithm" "Number Theory" "Numerical Methods" "Basics of Numbers" "Java" "Computational Geometry" "Math" "Physics" "ASCII Table") for ((i=1; i<${#array[@]}+1; ++i)); do echo "# $i. ${array[$i]}" > ${array[$i]}.md done