List information about directories and files, the current directory by default.

# To list files one per line:
ls -1

# To list all files, including hidden files:
ls -a

# To list all files, with trailing '/' added to directory names:
ls -F

# To long format list (permissions, ownership, size and modification date) of all files:
ls -la

# To long format list with size displayed using human readable units (KB, MB, GB):
ls -lh

# To long format list sorted by size (descending):
ls -lS

# To long format list of all files, sorted by modification date (oldest first):
ls -ltr