Practice Exercise: Comparing Files and Identifying File Types

Objectives

Learn how to compare files to find differences.
Understand how to identify different file types.
Gain hands-on experience using Linux commands for file comparison and type identification.

Scenario

As a Linux enthusiast, you want to become proficient in comparing files to find differences and identifying various file types on a Linux system. This exercise will guide you through the process of comparing files and recognizing file types using essential Linux commands.

Tasks

Task 1: Comparing Text Files

Create two text files, file1.txt and file2.txt, with some sample text in each.
Use the diff command to compare the contents of file1.txt and file2.txt.

Note any differences displayed by diff.

[intern@intern-a1t-inf-lnx1 ~]$ cat file1.txt
This line is similar
This line is different 49KditpKMhuOTQ==
[intern@intern-a1t-inf-lnx1 ~]$ cat file2.txt
This line is similar
This line is different i2BP9aUkUZ8NLg==
[intern@intern-a1t-inf-lnx1 ~]$   diff file1.txt file2.txt
2c2
< This line is different 49KditpKMhuOTQ==
---
> This line is different i2BP9aUkUZ8NLg==

As you can see it didn't output the similar line

Task 2: Identifying File Types

List the contents of a directory on your Linux system.
Identify at least five different types of files (e.g., text files, directories, executables, symbolic links, etc.) within the directory.
Use the file command to confirm the file types you identified.

Make a list of the identified file types and their descriptions.

# Create smaple empty file and directory
[intern@intern-a1t-inf-lnx1 ~]$ touch file1
[intern@intern-a1t-inf-lnx1 ~]$ mkdir dir1
[intern@intern-a1t-inf-lnx1 ~]$ file file1
file1: empty
[intern@intern-a1t-inf-lnx1 ~]$ file dir1
dir1: directory

# Check symbolic (soft link) file
[intern@intern-a1t-inf-lnx1 ~]$ ls -l /etc/yum.conf
lrwxrwxrwx. 1 root root 12 Jan 12  2023 /etc/yum.conf -> dnf/dnf.conf
[intern@intern-a1t-inf-lnx1 ~]$ file /etc/yum.conf
/etc/yum.conf: symbolic link to dnf/dnf.conf

# Check file with text content
[intern@intern-a1t-inf-lnx1 ~]$ file /etc/passwd
/etc/passwd: ASCII text
[intern@intern-a1t-inf-lnx1 ~]$ file /etc/sysctl.conf
/etc/sysctl.conf: ASCII text

# Check binary (executable) file
[intern@intern-a1t-inf-lnx1 ~]$ which cp
/usr/bin/cp
[intern@intern-a1t-inf-lnx1 ~]$ file /usr/bin/cp
/usr/bin/cp: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 3.2.0, BuildID[sha1]=cb11f66fba73c02b5b6211fd81d4f9b01c99c444, stripped

# Check block device file
[intern@intern-a1t-inf-lnx1 ~]$ ls -l /dev/sd*
brw-rw---- 1 root disk 8,  0 Oct 16 04:19 /dev/sda
brw-rw---- 1 root disk 8, 16 Oct 16 04:19 /dev/sdb
brw-rw---- 1 root disk 8, 32 Oct 16 04:19 /dev/sdc
[intern@intern-a1t-inf-lnx1 ~]$ file /dev/sda
/dev/sda: block special (8/0)

Task 3: Comparing Binary Files

Create two binary files, binary1.bin and binary2.bin, by copying a binary executable (e.g., /bin/ls) to two different names.
Use the cmp command to compare binary1.bin and binary2.bin.
Note if there are any differences reported by cmp.
Try to compare the binaries /bin/sh and /bin/bash
Note if there are any differences

[intern@intern-a1t-inf-lnx1 ~]$ cp /bin/ls binary1.bin
[intern@intern-a1t-inf-lnx1 ~]$ cp /bin/ls binary2.bin
[intern@intern-a1t-inf-lnx1 ~]$ cmp binary1.bin binary2.bin
[intern@intern-a1t-inf-lnx1 ~]$
[intern@intern-a1t-inf-lnx1 ~]$ cp /bin/sh sh.bin
[intern@intern-a1t-inf-lnx1 ~]$ cp /bin/bash bash.bin
[intern@intern-a1t-inf-lnx1 ~]$ cmp sh.bin bash.bin
sh.bin bash.bin differ: char 22, line 1

Task 4: Identifying Unknown Files

Locate an unknown file (e.g., a file without a file extension or with an unfamiliar extension) on your system.
Use the file command to identify the file type.
Research the identified file type to understand its purpose or use.

[intern@intern-a1t-inf-lnx1 ~]$ file binary1.bin
binary1.bin: Mach-O universal binary with 2 architectures: [x86_64:Mach-O 64-bit executable x86_64] [arm64e:Mach-O 64-bit executable arm64e]
binary1.bin (for architecture x86_64):  Mach-O 64-bit executable x86_64
binary1.bin (for architecture arm64e):  Mach-O 64-bit executable arm64e

Task 5: Using Wildcards

Create a directory with several files of different types, including text files, executables, and directories.
Use wildcards (e.g., * or ?) with commands like ls or file to identify specific types of files within the directory.
List all text files, executables, and directories separately using wildcards.

[intern@intern-a1t-inf-lnx1 ~]$ ls *.txt
NA.txt                  file2.txt               notebooks-data.txt      test2.txt
amp_workspaces.txt      file3.txt               output.txt              test3.txt
config-diff.txt         intern_testing_file.txt test-ldap.txt           usmsc30c.txt
env.txt                 less_than11.txt         test-sed.txt
file1.txt               lms.txt                 test1.txt
[intern@intern-a1t-inf-lnx1 ~]$ ls file?.txt
file1.txt file2.txt file3.txt

Conclusion

This practice exercise has allowed you to practice comparing text and binary files to find differences and identifying various file types on a Linux system. You've used essential commands like diff, file, and cmp to perform these tasks. Understanding how to compare files and recognize their types is essential for efficient file management and system administration in Linux.