Bash File Searching: Exercises, Solutions, and Explanations

Last update on April 24 2024 12:51:33 (UTC/GMT +8 hours)

Write a Bash script that searches for a file named "output.txt" in the current directory.

Code:

#!/bin/bash

# Search for file named "output.txt" in the current directory
if [ -f "output.txt" ]; then
    echo "File 'output.txt' found in the current directory."
else
    echo "File 'output.txt' not found in the current directory."
fi

Output:

File 'output.txt' found in the current directory.

Explanation:

In the exercise above,

if [ -f "output.txt" ]; then: This line checks if a file named "output.txt" exists in the current directory.

[ -f "output.txt" ] is a conditional expression that tests if "output.txt" exists and is a regular file.
If the file exists, the condition returns true, and the code inside the "if" block is executed.

echo "File 'output.txt' found in the current directory.": If the file "output.txt" exists in the current directory, this line prints a message indicating that the file is found.
else: If the condition in the "if" statement evaluates to false, meaning "output.txt" does not exist or is not a regular file, the code inside the "else" block is executed.
echo "File 'output.txt' not found in the current directory.": In the "else" block, this line prints a message indicating that the file "output.txt" is not found in the current directory.
fi: This marks the end of the "if" statement.

Write a Bash script that searches for a file with a specific name provided as an argument to the script.

Code:

#!/bin/bash

# Check if an argument is provided
if [ $# -ne 1 ]; then
    echo "Usage: $0 <filename>"
    exit 1
fi

# Get the filename from the command line argument
filename="$1"

# Check if the file exists in the current directory
if [ -f "$filename" ]; then
    echo "File '$filename' found in the current directory."
else
    echo "File '$filename' not found in the current directory."
fi

Output:

ad@DESKTOP-3KE0KU4:~$ ./test1.sh input.txt
File 'input.txt' found in the current directory.
ad@DESKTOP-3KE0KU4:~$ ./test1.sh document.doc
File 'document.doc' not found in the current directory.

Explanation:

In the exercise above,

if [ $# -ne 1 ]; then: Checks if the number of arguments provided is not equal to 1.
echo "Usage: $0 <filename>": Prints a usage message if the number of arguments is incorrect.
exit 1: Exits the script with a non-zero status code to indicate an error.
filename="$1": Assigns the first argument provided to the variable 'filename'.
if [ -f "$filename" ]; then: Checks if the file with the provided filename exists in the current directory.
echo "File '$filename' found in the current directory.": Prints a message if the file is found.
echo "File '$filename' not found in the current directory.": Prints a message if the file is not found.

Write a Bash script that searches for files modified within the last 3 days in the current directory.

Code:

#!/bin/bash

# Get the current time in seconds since the epoch
current_time=$(date +%s)

# Calculate the time 3 days ago in seconds since the epoch
three_days_ago=$((current_time - (3 * 24 * 60 * 60)))

# Iterate over each file in the current directory
for file in *; do
    # Check if the file was modified within the last 3 days
    if [ -f "$file" ] && [ $(stat -c %Y "$file") -ge "$three_days_ago" ]; then
        echo "$file"
    fi
done

Output:

abc.sh
erorrrr.log
input1.txt
input.txt
old_error.log
test1.sh
test.sh

Explanation:

In the exercise above,

current_time=$(date +%s): Gets the current time in seconds since the epoch.
three_days_ago=$((current_time - (3 24 60 * 60))): Calculates the time 3 days ago in seconds since the epoch.
for file in *; do: Iterates over each file in the current directory.
if [ -f "$file" ] && [ $(stat -c %Y "$file") -ge "$three_days_ago" ]; then: Checks if the file is a regular file (-f) and if its modification time (obtained using stat -c %Y "$file") is greater than or equal to the time 3 days ago.
echo "$file": Prints the filename if it meets the criteria.

Write a Bash script that searches for files larger than 1KB in the current directory.

Code:

#!/bin/bash

# Iterate over each file in the current directory
for file in *; do
    # Check if the file size is greater than 1KB (1024 bytes)
    if [ -f "$file" ] && [ $(stat -c %s "$file") -gt 1024 ]; then
        echo "$file"
    fi
done

Output:

output.txt

Explanation:

In the exercise above,

for file in *; do: Iterates over each file in the current directory.
if [ -f "$file" ] && [ $(stat -c %s "$file") -gt 1024 ]; then: Checks if the file is a regular file (-f) and if its size in bytes (obtained using stat -c %s "$file") is greater than 1024 bytes (1KB).
echo "$file": Prints the filename if it meets the criteria.

Write a Bash script that searches for empty files in the current directory.

Code:

#!/bin/bash

# Iterate over each file in the current directory
for file in *; do
    # Check if the file is empty (has size 0)
    if [ -f "$file" ] && [ ! -s "$file" ]; then
        echo "$file"
    fi
done

Output:

input1.txt
input.txt

Explanation:

In the exercise above,

for file in *; do: Iterates over each file in the current directory.
if [ -f "$file" ] && [ ! -s "$file" ]; then: Checks if the file is a regular file (-f) and if its size (obtained using ! -s "$file") is 0, indicating it's empty.
echo "$file": Prints the filename if it meets the criteria.

Write a Bash script that searches for files with a specific extension (e.g., "txt") in the current directory.

Code:

#!/bin/bash
# Enable globbing to include hidden files
shopt -s dotglob
# Specify the extension to search for
extension="txt"
# Iterate over each file in the current directory
for file in *; do
    # Check if the file has the specified extension
    if [ "${file##*.}" = "$extension" ]; then
        echo "$file"
    fi
done

Output:

input1.txt
input.txt

Explanation:

In the exercise above,

extension="txt": Specifies the extension to search for.
for file in *; do: Iterates over each file in the current directory.
${file##*.}: Extracts the file extension.
if [ "${file##*.}" = "$extension" ]; then: Checks if the extracted extension matches the specified extension.
echo "$file": Prints the filename if it has the specified extension.

Write a Bash script that searches for files containing a specific string provided as an argument to the script.

Code:

#!/bin/bash

# Check if the argument is provided
if [ $# -eq 0 ]; then
    echo "Usage: $0 <search_string>"
    exit 1
fi

# Extract the search string from the command line argument
search_string="$1"

# Iterate over each file in the current directory
for file in *; do
    # Check if the file is a regular file and contains the search string
    if [ -f "$file" ] && [ $(grep -q "$search_string" "$file"; echo $?) -eq 0 ]; then
        echo "$file"
    fi
done

Output:

ad@DESKTOP-3KE0KU4:~$ ./test1.sh shell
file2.txt
output.txt
sample.txt

Explanation:

In the exercise above,

$# -eq 0: Checks if no command-line arguments are provided.
echo "Usage: $0 <search_string>": Prints usage instructions if no argument is provided.
search_string="$1": Extracts the search string from the command-line argument.
for file in *; do: Iterates over each file in the current directory.
if [ -f "$file" ] && [ $(grep -q "$search_string" "$file"; echo $?) -eq 0 ]; then: Checks if the file is a regular file and contains the search string using grep.
echo "$file": Prints the filename if it contains the search string.

Write a Bash script that searches for files owned by a specific user in the current directory.

Code:

#!/bin/bash

# Check if the username is provided as an argument
if [ $# -eq 0 ]; then
    echo "Usage: $0 <username>"
    exit 1
fi

# Extract the username from the command-line argument
username="$1"

# Search for files owned by the specified user in the current directory
find . -maxdepth 1 -type f -user "$username"

Output:

ad@DESKTOP-3KE0KU4:~$ ./test1.sh ad
./.bash_history
./.bash_logout
./.bashrc
./.profile
./.viminfo
./abc.sh
./document.txt
./erorrrr.log
./file2.txt
./input.txt
./input1.txt
./nums.txt
./old_error.log
./output.txt
./sample.txt
./test.sh
./test1.sh
ad@DESKTOP-3KE0KU4:~$ ./test1.sh us
find: 'us' is not the name of a known user

Explanation:

In the exercise above,

$# -eq 0: Checks if no command-line arguments are provided.
echo "Usage: $0 <username>": Prints usage instructions if no argument is provided.
username="$1": Extracts the username from the command-line argument.
find . -maxdepth 1 -type f -user "$username": Searches for files (-type f) owned by the specified user (-user "$username") in the current directory (.) without descending into subdirectories (-maxdepth 1).

Write a Bash script that searches for symbolic links in the current directory.

Code:

#!/bin/bash

# Search for symbolic links in the current directory
find . -maxdepth 1 -type l

Output:

./my_link

Explanation:

In the exercise above,

find .: Start searching from the current directory.
-maxdepth 1: Limits the search to the current directory without descending into subdirectories.
-type l: Specifies that only symbolic links should be considered.

10.

Write a Bash script that searches for files with execute permissions in the current directory.

Code:

#!/bin/bash

# Search for files with execute permissions in the current directory
find . -maxdepth 1 -type f -executable

Output:

./test.sh
./test1.sh

Explanation:

In the exercise above,

find .: Start searching from the current directory.
-maxdepth 1: Limits the search to the current directory without descending into subdirectories.
-type f: Specifies that only regular files should be considered (not directories or other types of files).
-executable: Filters the search to include only files with execute permissions.

Bash Editor:

More to Come !

Do not submit any solution of the above exercises at here, if you want to contribute go to the appropriate exercise page.