Bash in Jupyter Notebooks

by Audrey M. Roy Greenfeld | Sun, Dec 29, 2024

## Variables

%%bash
name="Uma"
echo "Hi $name"
echo "Note: it's safer to quote variables like ${name}"

%%bash
echo "${name}"

! is like %%bash for one-line commands:

!name="Daniel"; echo "Hi ${name}"

!echo "Hi ${name}"

Variables don't persist across cells, for %%bash or !. Each cell's commands run in its own subshell.

Constants

%%bash
readonly UMA="the sweetest"
echo "Uma is ${UMA}"

Control Flow

%%bash
a=5
b=4
if [ "$a" -eq "$b" ]; then
    echo "Equal"
elif [ "$a" -gt "$b" ]; then
    echo "Greater"
else
    echo "Less"
fi

%%bash
for i in {1..5}; do
    echo $i
done

%%bash
count=2
while [ $count -lt 5 ]; do
    echo $count
    ((count++))
done

Functions

%%bash
greet() {
    echo "Hello $1"  # $1 is first argument
    return 0
}
greet "Uma the cutie"

Arrays

%%bash
fruits=("apple" "banana" "orange")
echo "First fruit: ${fruits[0]}"
echo "All fruits: ${fruits[@]}"