by Justin Li <email@example.com>, 2018-10-03
Most commands looks like this:
ls -l code
ls) is the command. Different commands do different things.
-l) is an option. They change how the commands work.
code) is an argument. They specify what the command acts on.
Options are always optional. Some commands (and some options) have required arguments. In this cheat sheet,
<argument> means that the argument is required;
[argument] means that the argument is optional.
<command> --help- Calling the command with the
--helpoption will often print out a short help message.
<command>- Many commands have a manual you can read. It's on the verbose side and is not always easy to understand, but it's built into every system.
exit- Log out of the command line.
top) use the Q key to quit.
pwd- Print the present working directory (ie. the current folder) you are in.
[path]- Change directory to the given path. If no path is given, changes to your home directory.
[path]- List the contents of the given path, or the current directory if none is given. Common options include
-ato show all files and
-lto use the long format (ie. more details).
<path>- Make a directory (the given path). Use
-pto also create intermediate (prerequiste) directories as needed.
<path>- Move a file to a directory.
<path>- Copy a file to a directory.
<file>- Remove a file. This does not ask for confirmation and cannot be undone.
<path>- Remove a directory. Only works if the directory is already empty. This does not ask for confirmation and cannot be undone.
<file>- Display a file. Press
<file>- Edit a file. The available commands are listed at the bottom, with the
^meaning CTRL (eg. CTRL+X to exit).
<file>- Print the first 10 lines of a file. Use
-n 20to print (for example) the first 20 lines.
<file>- Print the last 10 lines of a file. Use
-n 20to print (for example) the last 20 lines.
<file>- Show a word count of a file.
<file>- Sort a file by lines. Use
-ito ignore case and
-nto treat the lines as numbers.
<file>- Print the lines where
-ito ignore case and -r to recursively search through directories.
uniq- Print the
unique lines of a file. Assumes the file to be sorted first. Use
-dto show duplicates instead and
-cto count each unique line.
date- Print the current date.
uptime- Print how long the computer has been on.
top- Show the most active programs. Press q to quit.
df- Show the amount of space available on the hard disk. Use
-hto get human-readable sizes.
<file>- Show the amount of space taken up by the file. The current directory is used if no file is given. Use
-hto get human-readable sizes, and
-sto get separate sizes for each file.
uname- Print system information. Use
-ato show all information.
[[month] year]- Print a calendar, optionally specifying year and month.
<file2>- Find the difference between two files. Use
-yto show the files side-by-side.
|), so the output of one becomes the input of the other. For example,
head <file> | sort | uniq -cwill count the unique items in the first ten lines of a file.
grep), the text could be the output of another command. For example,
grep "$(head -n 1 <file1>)" <file2>will search
file2for the first line of