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Ruby program to open a file in the read-write mode without truncating the file

Last Updated : December 15, 2025

Problem Solution

In this program, we will open a file in read-write mode using the File class in 'r+' mode. Then we will read and write data into the file.

Program/Source Code

The source code to open a file in the read-write mode without truncating the file is given below. The given program is compiled and executed on Windows 10 Operating System successfully.

# Ruby program to open a file in the 
# read-write mode without 
# truncating the file

# Open file in read-write mode.
fobj = File.new("MyFile.txt", "r+"); 

print "File opened in read write mode.\n";

# Read data from file
puts fobj.read();

# Write data into file
fobj.syswrite("India\n");

# Close file object
fobj.close();  

# Open file in read mode.
fobj = File.new("MyFile.txt", "r"); 

print "File opened in read mode.\n";

# Read data from file
puts fobj.read();

# Close file object
fobj.close();  

Output

File opened in read write mode.
Hello World
File opened in read mode.
Hello World
India

Explanation

In the above program, we opened a file "MyFile.txt" in read-write mode ('r+') by creating object fobj of the File class. Then we read data from the file and write data into the file. After that, we read the updated file and printed the result.

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