Local Variables

local x=something y

X is initialized. Y is declared only
Dynamically scoped

Arrays

crew=(kermit piggy frozzie) # Initialize array
crew[3]='sam eagle' # Adds a 4th item 'sam eagle'
echo ${crew[1]} # Gets item 1 (piggy)
crew+=(gonzo 'dr pepper')
echo ${#crew[@]} # Gets number of items in array
 
for c in "${crew[@]}" ; do # iterates over all items
    echo $c
done
 
for i in $(seq 1 ${#crew[@]} ) ; do
	echo ${crew[$((i - 1))]}
done

Output is as follows:

piggy  
6  
kermit  
piggy  
frozzie  
sam eagle  
gonzo  
dr pepper

goes-in-cheat-sheet-DONE

”Dictionaries” (Associative Arrays)

Always string indexes

declare -A mark # Required to do. Makes "mark" a dict
mark=([denise]=4 [bob]=9)
mark[charles]=3
mark+=([bob]=7 [alice]=5])
for k in "${!mark[@]}" ; do
	echo "$k has ${mark[$k]} marks"
done

Process Substitution

cmd1 | cmd2 connects 1 command to another. But what if you want a command to take more than 1 inputs? cmd <(cmd1) <(cmd2)

Run cmd1 and redirect to temp file
Run cmd2 and redirect to another temp file
Those temp files are appended into cmd as if it was the stdin

Also… this (but idk why this exists): foo >(cmd1)

Sends foo into cmd1

todo https://www.cs.utoronto.ca/~trebla/CSCB09-2025-Summer/08-shell-l.pdf#Navigation45

What is the last slide on this!?