Post Lab activity1
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This document provides instructions for a laboratory activity on basic Unix commands. It discusses how to log in and out of a Unix system, interpret the command prompt, enter commands, and perform basic file management tasks. These include changing directories, listing files, creating directories, copying and moving files. The document contains steps for students to perform these commands and answer questions to familiarize themselves with basic Unix/Linux functionality.
![3c. What is the prompt sign on your screen?
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1.3. Entering Commands
Commands can be entered to the Unix server via the command prompt. This is usually done by typing a series of
characters after the prompt sign. A usual format in entering commands is:
[dwight@netopsy1 greg]$ command <options> <argument>
Options for the command are switches that tell a command to do something differently. Arguments are information
sometimes needed by the command to be able to execute properly. Most of the time, options and arguments are not
needed in a command.
There are also commands wherein you do not need to type anything. These commands are: ctrl-c, ctrl-d, ctrl-s, and
ctrl-d. The table below gives a short description.
Step 4 On the command prompt, type “man –S 1 pwd” and press enter. This command will be tackled later in the
course, for now just accept it.
4a. What is the option in the command?
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4b. What is the argument in the command?
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4c. Press “q” to exit the command.
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Step 5 On the command prompt, type “top” and press enter.
5a. Press the control and “c” key at the same time. What happened? Did it have the same effect as pressing “q”?
Why”
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![13d. Enter the “ls -l” command. What is the option? Was it different from last time? What does it do?
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The first column on the “ls -l” shows the file permission of the file or directory (again, will be discussed later).
Notice that a “d” as the first character shows which are the directories.
13e. Enter “cd /etc” and then the “ls -d rc0.d” command. What is the option? What does it do? Is it different from the “ls
rc0.d” command?
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The “d” displays if the “rc0.d” directory is there or not. While the “ls” command without the “d” option will display
the contents of the directory “rc0.d”.
13f. Enter the “ls -R” command. What is the option? What does it do? How is it different from “ls”.
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The “R” option displays the directories recursively.
Step 14 Metacharacters are characters with special meaning in Unix. One of the metacharacters is “*”.
14a. Go to the “/home/dir1” directory, type the command “ls f*”. What files were listed?
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14b. Enter the command “ls p*”. What files were listed?
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14c. Enter the command “ls file?”. What files were listed?
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14d. What is the difference between the commands “ls f*” and “ls file?”?
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14e. Enter the command “ls [f..p]ile1”. What files were listed?
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![14f. Enter the command “ls [f..p]ile2”. What files were listed?
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14g. Enter the command “ls [f..p]ile?”. What files were listed?
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14h. What does the metacharacter “[..]” do?
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The metacharacter “*” is a wildcard for multiple characters while “?” is wildcard for a single character. The
metacharacter “[..]” is used to specify a range of characters.
1.5.3. Creating Directories
Directories in the Unix operating system can be created using the “mkdir” command. Naming directories has the same
rules as naming files. Exercises on filenames will be tackled later.
Step 15 Go to your home directory by entering the command “cd ~”. Then create a directory “coffees” using the
command “mkdir coffees”.
15a. Was the directory created?
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15b. Enter the command “cd coffees” and press enter. Next, enter the command “mkdir beans/robusta”. Were
you able to create the directory?
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15c. Enter the command “mkdir -p beans/robusta”. Were you able to create the directory? Why do you think so?
What is the “p” option for?
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The “p” option allows creation of directories with its parent directory.
1.5.4. Filenames
Empty files are files with a size of zero bytes. The “touch” command can be used to create empty files. The “touch”
command will be used to practice creating files with different filenames.
In Unix, filenames can have up to 255 printable characters except for the “/” character. Although “*” and “?” can be
used, these characters have special meaning.
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Post Lab activity1
- 1. Laboratory Activity 1 Name: __________________________________ Date: _____________ Unix Basic Commands 1.0 Unix / Linux Command Line Interface (CLI) Basics – Basic Commands This section of the course provides a discussion and hands-on guide on the basic CLI commands in Unix/Linux. The basic CLI commands are: how to log-in, log-out, interpreting the command prompt, how to enter commands, basic file commands and management, and simple file permission. The objectives of this section are: • Familiarize the students on how to gain access to a Unix/Linux server. • Familiarize the students on what is the prompt and how to enter commands. • Familiarize the students on file identifiers and, relative and absolute file names. • Familiarize the students on basic file commands and management. 1.1. Logging In To access a Unix/Linux server, a Telnet or SSH client software can be used to connect to the server. Most operating system today has some form of this software like “putty.exe”. A login prompt for a Unix server can look like: Login: <username> Password: Before you try to log-in to a Unix server, ask your instructor for a user account, and the IP address or server name where your account is valid. After acquiring the user account and the server you are assigned to, accomplish the following: Step 1 On your Windows operating system, use an ssh client program to connect to the Unix server. Using the “putty” client program, enter the IP address or name of the Linux server in the “Host Name” text box and click the “Open” button. 1
- 2. Step 2 At the login prompt, type your assigned username and password. 2a. Were you able to login? How were you able to login? _________________________________________________________________________ _________________________________________________________________________ 2b. Did you have a user account when you logged-in? _________________________________________________________________________ _________________________________________________________________________ 2c. What is the IP address or server name of the Unix server you logged into? _________________________________________________________________________ _________________________________________________________________________ 1.2. The Command Prompt After you have logged-in, notice that a prompt will appear on the screen. A prompt is an interface that allows user to input commands. Different shells use different faces of prompts (shells will be tackled later in the course). In this server, you will be greeted with: Notice the different parts of your prompt. For the example prompt, it has displayed the username, current directory you are in, the computer name and the prompt sign. Step 3 Write down the prompt on your screen. _________________________________________________________________________ _________________________________________________________________________ 3a. Is your username displayed on the prompt? What is your username? _________________________________________________________________________ _________________________________________________________________________ 3b. Is a computer name displayed on the prompt? What is the computer name? _________________________________________________________________________ _________________________________________________________________________ 2
- 3. 3c. What is the prompt sign on your screen? _________________________________________________________________________ _________________________________________________________________________ 1.3. Entering Commands Commands can be entered to the Unix server via the command prompt. This is usually done by typing a series of characters after the prompt sign. A usual format in entering commands is: [dwight@netopsy1 greg]$ command <options> <argument> Options for the command are switches that tell a command to do something differently. Arguments are information sometimes needed by the command to be able to execute properly. Most of the time, options and arguments are not needed in a command. There are also commands wherein you do not need to type anything. These commands are: ctrl-c, ctrl-d, ctrl-s, and ctrl-d. The table below gives a short description. Step 4 On the command prompt, type “man –S 1 pwd” and press enter. This command will be tackled later in the course, for now just accept it. 4a. What is the option in the command? _________________________________________________________________________ _________________________________________________________________________ 4b. What is the argument in the command? _________________________________________________________________________ _________________________________________________________________________ 4c. Press “q” to exit the command. _________________________________________________________________________ _________________________________________________________________________ Step 5 On the command prompt, type “top” and press enter. 5a. Press the control and “c” key at the same time. What happened? Did it have the same effect as pressing “q”? Why” _________________________________________________________________________ _________________________________________________________________________ 3
- 4. Step 6 On the command prompt, type ”man chmod” and press enter. 6a. Press the spacebar. Did the screen scroll up? _________________________________________________________________________ _________________________________________________________________________ 6b. Press the control and “s” key at the same time and then press the spacebar. Did the screen scroll up? Why? _________________________________________________________________________ _________________________________________________________________________ 6c. This time press the control and “q” key at the same time. What happened? ________________________________________________________________________ _________________________________________________________________________ 6d. What does the command “ctrl-s” and “ctrl-q” do? ________________________________________________________________________ _________________________________________________________________________ 1.4. Changing Password One of the first things you must do on your user account is to change your password. Password ensures that no one will have unauthorized access to your user account. A user must have to be authenticated using a password before access to server will be given. To change your password, use the command: passwd. You will be prompted by the server of your old password and then will be prompted to input a new password. You will have to re-type your new password for verification. You can change your password anytime. Password must have at least six characters with any alphanumeric combination (at least for Linux) but is case sensitive. Step 7 At the command prompt, type “passwd”. 7a. Enter your current password when prompted for the old password. 7b. Enter the password “h3ll0”, when prompted for the new password. 7c. Was the password rejected? Why was it rejected? ________________________________________________________________________ _________________________________________________________________________ 7d. Enter the password “r3ch3tt” when prompted for the new password. 7e. Was the password was accepted? Why was it accepted? ________________________________________________________________________ _________________________________________________________________________ 7f. What is the message when the password was successfully changed? ________________________________________________________________________ _________________________________________________________________________ 4
- 5. Step 8 At the command prompt, type “passwd“ again. Type the current password as “R4ch3tt”. 8a. Was the password rejected? Why was it rejected? ________________________________________________________________________ _________________________________________________________________________ 8b. What is the message when the password was not successfully changed? ________________________________________________________________________ _________________________________________________________________________ Step 9 At the command prompt, type “passwd“ again. Enter the current password. Use your desired password when prompted for a new password. Remember your new password. 9a. Were you able to give a new password on your first try? What were the messages from the server? ________________________________________________________________________ _________________________________________________________________________ 1.5. Basic File Management Unix file system, like other file systems of other operating systems, consists of files and each file has a file name. There are three kinds of files on your Unix system: ordinary, special and directories. The Unix file system is organized as a hierarchy of directories where each directory can contain files or subdirectories. This hierarchy is called a tree where the root (/) is the top of the tree. Each file in a directory has a file identifier (this is not synonymous to file name), which is a sequence of characters that uniquely identifies a file or directory. A file identifier can have at most 255 characters (this includes extension); any printable character can be used as to name a file but cannot contain “/”. Although the characters “*”, “?”, “>”, “>” or “|”, it is not recommended because it has special meaning. Remember that filenames in Unix are case sensitive. File names in Unix, contains a sequence of file identifiers that designates a file. Slashes “/” are used to separate the sequence of file identifiers. There are two kinds of file name: absolute and relative file name. Absolute file name specifies the sequence of directories starting from the root (it actually starts with a “/”) and can be used to refer to a file anywhere in the tree. Relative file name’s starting point is the current directory or working directory. Relative file name can use symbols “.” and “..” which represents the current directory and parent directory respectively. Another symbol “~”, represents the home directory. Home directory is the personal directory of a user where your files can be stored. In order to do basic file management, there are several basic commands that can be used. Usual commands needed are to list files in a directory, change to another directory, create a new directory, move a file or directory, copy a file or directory, and remove a file or directory. Most of the commands can use absolute or relative filenames. The commands are presented in a table below. 5
- 6. 1.5.1. Changing to different directories The “cd” command is used to change the working directory. Every time you log in via Telnet, you will be in your home directory. Most of the time, your directory is located in the “/home” parent directory. The hierarchy can be shown as: The hierarchy shown is very simple. This is not the whole hierarchy for the Unix system. Also, not all hierarchy is the same for all Unix versions. Step 10 While you are in the home directory, type the command “pwd”. 10a. What was the message on the screen? ________________________________________________________________________ _________________________________________________________________________ 10b. What does the “pwd” command do? ________________________________________________________________________ _________________________________________________________________________ Step 11 Type the command “cd /etc” and press enter. 11a. Did the prompt display differently? Write down the display. ________________________________________________________________________ _________________________________________________________________________ 11b. Type the command “pwd”. What is your current working directory? ________________________________________________________________________ _________________________________________________________________________ 6
- 7. Step 12 From the “/etc” directory, type the command “cd /home/<username>”. 12a. Did you go to your “home” directory? How were you able to determine? ________________________________________________________________________ _________________________________________________________________________ 12b. What was the file name used (absolute or relative file name)? Why? ________________________________________________________________________ _________________________________________________________________________ 12c. On the command prompt, type “cd ../../etc” and press enter. Were you able to go to the “/etc” directory? What was the file name used (absolute or relative file name)? Why? ________________________________________________________________________ _________________________________________________________________________ 12d. From the “/etc” directory, type the command “cd ~”. Were you able to go to the “home” directory? Which “cd” command is this similar to? ________________________________________________________________________ _________________________________________________________________________ 1.5.2. Listing Directories The “ls” command is used to list directories. There are a lot of options you can do with the command. It is able to display all files, directories only and other more options. Step 13 On the command prompt, type the command “cd ..” and press enter. 13a. Enter the “ls” command. What did you see? ________________________________________________________________________ _________________________________________________________________________ 13b. Enter the “ls -A” command. What is the option? Was it different from last time? ________________________________________________________________________ _________________________________________________________________________ 13c. Enter the “ls -a” command. What is the option? Was it different from last time? What does it do? ________________________________________________________________________ _________________________________________________________________________ The “ls” command with option “A”, shows all files in the directory including hidden files. Hidden files are files that start with “.”. The “a” option has the same function as “A” option except that it also displays the “.” (current) and “..” (parent) directories. 7
- 8. 13d. Enter the “ls -l” command. What is the option? Was it different from last time? What does it do? ________________________________________________________________________ _________________________________________________________________________ The first column on the “ls -l” shows the file permission of the file or directory (again, will be discussed later). Notice that a “d” as the first character shows which are the directories. 13e. Enter “cd /etc” and then the “ls -d rc0.d” command. What is the option? What does it do? Is it different from the “ls rc0.d” command? ________________________________________________________________________ _________________________________________________________________________ The “d” displays if the “rc0.d” directory is there or not. While the “ls” command without the “d” option will display the contents of the directory “rc0.d”. 13f. Enter the “ls -R” command. What is the option? What does it do? How is it different from “ls”. ________________________________________________________________________ _________________________________________________________________________ The “R” option displays the directories recursively. Step 14 Metacharacters are characters with special meaning in Unix. One of the metacharacters is “*”. 14a. Go to the “/home/dir1” directory, type the command “ls f*”. What files were listed? ________________________________________________________________________ _________________________________________________________________________ 14b. Enter the command “ls p*”. What files were listed? ________________________________________________________________________ _________________________________________________________________________ 14c. Enter the command “ls file?”. What files were listed? ________________________________________________________________________ _________________________________________________________________________ 14d. What is the difference between the commands “ls f*” and “ls file?”? ________________________________________________________________________ _________________________________________________________________________ 14e. Enter the command “ls [f..p]ile1”. What files were listed? ________________________________________________________________________ _________________________________________________________________________ 8
- 9. 14f. Enter the command “ls [f..p]ile2”. What files were listed? ________________________________________________________________________ _________________________________________________________________________ 14g. Enter the command “ls [f..p]ile?”. What files were listed? ________________________________________________________________________ _________________________________________________________________________ 14h. What does the metacharacter “[..]” do? ________________________________________________________________________ _________________________________________________________________________ The metacharacter “*” is a wildcard for multiple characters while “?” is wildcard for a single character. The metacharacter “[..]” is used to specify a range of characters. 1.5.3. Creating Directories Directories in the Unix operating system can be created using the “mkdir” command. Naming directories has the same rules as naming files. Exercises on filenames will be tackled later. Step 15 Go to your home directory by entering the command “cd ~”. Then create a directory “coffees” using the command “mkdir coffees”. 15a. Was the directory created? ________________________________________________________________________ _________________________________________________________________________ 15b. Enter the command “cd coffees” and press enter. Next, enter the command “mkdir beans/robusta”. Were you able to create the directory? ________________________________________________________________________ _________________________________________________________________________ 15c. Enter the command “mkdir -p beans/robusta”. Were you able to create the directory? Why do you think so? What is the “p” option for? ________________________________________________________________________ ___________________________________________________________________________________________ The “p” option allows creation of directories with its parent directory. 1.5.4. Filenames Empty files are files with a size of zero bytes. The “touch” command can be used to create empty files. The “touch” command will be used to practice creating files with different filenames. In Unix, filenames can have up to 255 printable characters except for the “/” character. Although “*” and “?” can be used, these characters have special meaning. 9
- 10. Step 16 While in the directory “coffees/beans/robusta”, enter the command “touch robusta.txt”. 16a. Were you able to create the file? What is the size of the file? How were you able to determine the file size? ________________________________________________________________________ ___________________________________________________________________________________________ 16b. Enter the command “touch robusta/txt“. Were you able to create the file? Why? What was the message? ________________________________________________________________________ ___________________________________________________________________________________________ 16c. Enter the command “touch robusta1“. Were you able to create the file? Why? ________________________________________________________________________ ___________________________________________________________________________________________ 16d. Enter the command “mkdir robusta.doc“. Were you able to create the directory? Why? ________________________________________________________________________ ___________________________________________________________________________________________ 16e. Enter the command “ls“. Can you tell which one is a directory? What command should be used to be able to determine which one is a directory? ________________________________________________________________________ ___________________________________________________________________________________________ 16f. Enter the command “ls robusta*“. Is there a difference from the earlier command? Can you tell which one is the directory? Why? ________________________________________________________________________ ___________________________________________________________________________________________ 1.5.5. Copying Files The cp command is used to copy files. The command can be used to copy one source to a destination or multiple sources to a directory. Step 17 Enter the command “cp robusta.txt robusta.html”. 17a. What happened after entering the command? Did you see the file “robusta.html”? ________________________________________________________________________ ___________________________________________________________________________________________ 17b. Enter the command “cp robusta.txt robusta.doc”. What happened after entering the command? Did you see the file “robusta.doc“? Why? ________________________________________________________________________ ___________________________________________________________________________________________ 10
- 11. 17c. Enter the command “cp robusta.txt robusta.html”. Were you prompted if the file was to be overwritten? Why? ________________________________________________________________________ ___________________________________________________________________________________________ 17d. Enter the command “cp –i robusta.txt robusta.html”. Were you prompted if the file was to be overwritten? Why? ________________________________________________________________________ ___________________________________________________________________________________________ 1.5.6. Moving Files In the Unix operating system, moving of files can be done by using the command “mv”. The command can also be used to rename files. Step 18 Enter the command “mkdir -p ../arabica” and press enter. Next, enter the command “touch arabica.txt”. Use the command “ls” to verify the file is existent. 18a. Enter the command “mv arabica.txt ../arabica”. Is the file “arabica.txt” still there? Where is it located now? What did the command “mv” do? ________________________________________________________________________ ____________________________________________________________________________________ 18b. Enter the command “touch arabica.txt” under the directory “<home directory>/coffees/beans/robusta”. Next, type the command “mv arabica.txt ../arabica”. What happened? Were you prompted that you will be overwriting a file? ________________________________________________________________________ _____________________________________________________________________________________ 18c. Enter the command “touch arabica.txt” under the directory “<home directory>/coffees/beans/robusta”. Next, type the command “mv –i arabica.txt ../arabica”. What happened? Were you prompted that you will be overwriting a file? ________________________________________________________________________ _____________________________________________________________________________________ Answer no to the prompt. 18d. Enter the command “mv arabica.txt arabica.doc”. What happened? Is the file still there? Why? ________________________________________________________________________ _____________________________________________________________________________________ 11
- 12. The command can be used to rename files. 18e. What is the difference between the command “cp arabica.txt ../arabica” and “mv arabica.txt ../arabica”. Explain. ________________________________________________________________________ _____________________________________________________________________________________ 1.5.7. Removing Files Removing or deleting files can be accomplished by using the command “rm”. Be careful in using this command since deleted file are unrecoverable. Step 19 Go to the “<home directory>/coffees/beans/robusta” directory. Type the command “rm arabica.doc”. 19a. Was the file still there? Can it be found in another directory? Why? ________________________________________________________________________ _____________________________________________________________________________________ Step 20 Enter the command “rm *”. 20a. What happened? Which file or directory was retained? ________________________________________________________________________ _____________________________________________________________________________________ 20b. Why was it retained? ________________________________________________________________________ _____________________________________________________________________________________ Step 21 Go to the “robusta.doc” directory. Create the following directory “bean_quality” and “bean_quality/perfect_cup”. 21a. Go to the “<home directory>/coffees/beans/robusta”. Enter the command “rm robusta.doc”. Were you able to remove the directory? Why? ________________________________________________________________________ _____________________________________________________________________________________ 21b. Enter the command “rm -r robusta.doc”. Were you able to remove the directory? Why? What is the option “r” for? ________________________________________________________________________ _____________________________________________________________________________________ Step 22 Go to the “arabica” directory. Enter the command “rm –i arabica.txt”. 22a. Was the file erased immediately? What was the message? ________________________________________________________________________ _____________________________________________________________________________________ 12
- 13. 22b. Answer “y” to the prompt. Was the file removed? What is the option “i” for? ________________________________________________________________________ _____________________________________________________________________________________ 22c. Go to the “<home directory>/coffees” directory and enter the command “rm -ir robusta.doc”. Were prompted before removal? What was the message? ________________________________________________________________________ _____________________________________________________________________________________ Answer “n” to the prompt. 1.6. Logging Out The “exit” command can be used to log out of the Unix server. Step 23 At the prompt type the command “exit”. 23a. What happened? Were you able to log out? Is there an alternative command? (You may research this on books or in the Internet) ________________________________________________________________________ _____________________________________________________________________________________ 13