Basic UNIX commands: Difference between revisions

Latest revision as of 20:23, 29 December 2020

Here is a list of some common UNIX commands. This should get you started.

Command	What for	Advanced version	What does it do?
`man`	manual for UNIX commands	`man man`	First command to learn, manual on manual
`ls`	list contents of directory	`ls -latr`	list all files with more information, sort in reverse order than when it was created
`cd`	change directory	`cd -`	change to the last directory you were in
`cp`	copy files/directories	`cp -a`	copy while preserving all properties
`mv`	move file (change name)	`mv -i`	move but ask if you are overwriting an existing file
`rm`	remove (delete)	`rm -rf *`	delete everything, without asking and without mercy (very dangerous)
`less`	view an ASCII file	`less -S a.txt`	View `a.txt` without wrapping long lines

Command	What for	Example	What does it do?
chmod	Change access permissions in UNIX	`chmod 755 a.txt`	Allows everyone to read and execute the file `a.txt`
diff	compare two files and list differences	`diff a b`	COmpare the two files `a` and `b` and list differences
grep	print lines that match a pattern	`grep -i err a.log`	Print all the lines in the file `a.log` that contain `err` written big or small.
ps	List UNIX processes running	`ps -auxw`	List all processes for all users
sort	Sort text files line by line	`sort -nr a.txt`	Sort lines of `a.txt` in reverse numerical order

Tool	What is it used for
awk	modify files based on patterns
find	look for files that match a criteria
sed	replaces strings in text file
vi	Standard UNIX text editor

@@ Line 19: / Line 19: @@
 <tr> <th>Command</th>   <th>What for</th>                               <th>Example</th>                          <th>What does it do?</th>  </tr>
 <tr> <th>[[chmod]]</th>  <td>Change access permissions in UNIX</td>     <td><code>chmod 755 a.txt</code></td>     <td>Allows everyone to read and execute the file <code>a.txt</code></td></tr>
+<tr> <th>[[diff]]</th>  <td>compare two files and list differences</td> <td><code>diff a b</code></td>   <td>COmpare the two files <code>a</code> and <code>b</code> and list differences</td></tr>
 <tr> <th>[[grep]]</th>  <td>print lines that match a pattern</td>       <td><code>grep -i err a.log</code></td>   <td>Print all the lines in the file <code>a.log</code> that contain <code>err</code> written big or small.</td></tr>
 <tr> <th>[[ps]]</th>  <td>List UNIX processes running</td>              <td><code>ps -auxw</code></td>     <td>List all processes for all users</td></tr>