basic commands

A short list of some useful commands. Respect the presence, or absence, of spaces in the line.

Command Meaning DOS equivalent?
pwd Print Working Directory. This is "where you are" at the moment, the directory (folder) that commands will apply to. (prompt usually shows current directory)
ls List contents of current directory. DIR/w
ls -F List contents along with a "flag" that indicates whether each item is a directory, executable, or a symlink ("shortcut"). (The -F option can be combined with other options.)  
ls -l List permissions, owner, file size, and last-modified time of contents of current directory. (The -l option can be combined with other options.) DIR
ls -A List all contents of current directory, including hidden entries (names beginning a "."). (The -A option can be combined with other options.) DIR/a
cd new-dir Change directory: make new-dir be the current directory. CHDIR or CD
mkdir new-dir Make directory: create new-dir as a child of the current directory. MKDIR or MD
rmdir victim-dir Remove (delete) victim-dir. Fails if the directory isn't empty. RMDIR or RD
rm -i victim-file Remove victim-file. the "-i" option asks for verification (a good idea). DEL or ERASE
cp -isource-file new-file Copy source-file into new-file. If new-file already exists, it will be replaced. If-i is included, prompt for any replacement first. COPY or XCOPY
mv -isource-file new-file Move source-file into new-file. If new-file already exists, it will be replaced. If-i is included, prompt for any replacement first.

This command is used to move a file from one directory to another, and/or to rename a file from an old name ("source-file") to a new name ("new-file"). It is basically like the "cp" command, but removes the original file after copying it.

MOVE and RENAME
echo message Display message on the console. ECHO
cat target-file Display target-file to the console. TYPE
less target-file Display target-file, one screenful at a time. MORE
grep pattern target-file Find occurrences of pattern in target-file, and display the lines that contain that pattern. FIND
diff left-file right-file Compare left-file and right-file, show differences in an "add-line, delete-line" format.  
man command Get basic "manual page" for command. Generally, shows all options and required arguments, and describes them. HELP
bash Start the "bash" command interpreter. This provides <TAB>-completion, command history, and other features. CMD (or maybe POWERSHELL?)
which target-executable Find the directory the contains the target-executable program.  
./exe-file Run the exe-file executable from the current directory. (DOS looks in the current directory first.)
gcc -Wall -lm -o exe-file source-file Compile and link source-file to produce exe-file executable. Optionally, include the math library for math functions.  
python3
python3 .py-file
Start the python v3.x interpreter, either interactive or executing a source file. (same, from cmd prompt; or use the GUI "Search" dialog.)
python
python .py-file
Start the system default python interpreter, either interactive or executing a source file. (System default may be v2.x or v3.x) (same, from cmd prompt; or use the GUI "Search" dialog.)