If else

Shell if tests a condition in [ ]. Spaces inside the brackets are required.

if [ <condition> ]
        then
        ..
elif
        then
        ..
else
fi

elif is else-if. else has no then. The block ends with fi.

Condition

"$var" == "value"

On Ubuntu use = instead of ==.

Numerical

• -eq
• -ne
• -gt
• -lt
• -le
• -ge

String

• =
• !=
• < before alphabetically
• > after alphabetically