Below is a pretty thorough list of BASH commands
alias- Create an alias
awk- Find and Replace text within file(s)
break- Exit from a loop
builtin- Run a shell builtin
cal- Display a calendar
case- Conditionally perform a command
cat- Display the contents of a file
cd- Change Directory
chgrp- Change group ownership
chmod- Change access permissions
chown- Change file owner and group
chroot- Run a command with a different root directory
cksum- Print CRC checksum and byte counts
clear- Clear terminal screen
cmp- Compare two files
comm- Compare two sorted files line by line
command- Run a command - ignoring shell functions
continue- Resume the next iteration of a loop
cp- Copy one or more files to another location
cron- Daemon to execute scheduled commands
crontab- Schedule a command to run at a later time
csplit- Split a file into context-determined pieces
cut- Divide a file into several parts
date- Display or change the date & time
dc- Desk Calculator
dd- Data Dump - Convert and copy a file
declare- Declare variables and give them attributes
df- Report filesystem disk space usage
diff- Display the differences between two files
diff3- Show differences among three files
dir- Briefly list directory contents
dirname- Convert a full pathname to just a path
dirs- Display list of remembered directories
du- Estimate file space usage
echo- Display message on screen
ed- A line-oriented text editor (edlin)
egrep- Search file(s) for lines that match an extended expression
eject- Eject CD-ROM
enable- Enable and disable builtin shell commands
env- Display, set, or remove environment variables
eval- Evaluate several commands/arguments
exec- Execute a command
expand- Convert tabs to spaces
export- Set an environment variable
expr- Evaluate expressions
factor- Print prime factors
fdformat- Low-level format a floppy disk
fdisk- Partition table manipulator for Linux
fgrep- Search file(s) for lines that match a fixed string
