# 
# ls
# 
# List directory contents.
# 
# List files one per line:
  ls -1
# 
# List all files, including hidden files:
  ls -a
# 
# Long format list (permissions, ownership, size and modification date) of all files:
  ls -la
# 
# Long format list with size displayed using human readable units (KB, MB, GB):
  ls -lh
# 
# Long format list sorted by size (descending):
  ls -lS
# 
# Long format list of all files, sorted by modification date (oldest first):
  ls -ltr
# 
#