README.md

bash-script

me learning bash scripts

variable

variable=5
string='a string'
interpolated="variable value is ${variable}"

conditional

if [[ 5 -gt 4 ]]; then
  echo "always true"
fi


# $(( )) is used for any variable and arithmetic operators
if ((5 > 4)); then
  echo "always true"
fi

loops

# while loop
while (( a > b )); do
  echo b++
  b=$((++b))
done


# until aka do while
until (( b >= a)); do
  echo b++
  b=$((++b))
done

functions

function count(){
  for num in {1..10}; do
    echo $num
    sleep 1
  done
}

count_to_10

# sending parameters
function count(){
  count=1
  while (($count < $1)); do
    echo $count
    count=$((++count))
  done
}


count 5

string manipulation

# find length of string
echo ${#string}

# substring
# #echo ${string:start_index:length}
string="my array"
echo ${string:3:5} # => array

text manipulation

basic text manipulation tools are

• cut -> extract specific columns
• sed -> finding and replacing pattern
• awk -> scanning and processing
• tr -> translate or delete characters
• grep -> finding pattern