How do you delete a specific line from a text file in Java?
You want to do something like the following:
- Open the old file for reading.
- Open a new (temporary) file for writing.
- Iterate over the lines in the old file (probably using a BufferedReader) …
- When done, close both files.
- Delete the old file.
- Rename the temporary file to the name of the original file.
How do you delete a specific line in a file?
Using a Number to Delete a Line
- Open the file in read mode.
- Read the files contents.
- Open the file in write mode.
- Use a for loop to read each line and write it to the file.
- When we reach the line we want to delete, skip it.
How do you delete a specific file in Java?
In Java, we can delete a file by using the File. delete() method of File class. The delete() method deletes the file or directory denoted by the abstract pathname. If the pathname is a directory, that directory must be empty to delete.
How do I remove the first line from a text file in Java?
Scanner fileScanner = new Scanner(myFile); fileScanner. nextLine(); This will return the first line of text from the file and discard it because you don’t store it anywhere.
How do you replace a specific line in a file using Java?
Invoke the replaceAll() method on the obtained string passing the line to be replaced (old line) and replacement line (new line) as parameters. Instantiate the FileWriter class. Add the results of the replaceAll() method the FileWriter object using the append() method.
How can I clear the contents of a text file using Java?
How to delete a string inside a file(. txt) in java?
- Retrieve the contents of the file as a String.
- Replace the required word with an empty String using the replaceAll() method.
- Rewrite the resultant string into the file again.
How do you delete a line in a file Unix?
To Remove the lines from the source file itself, use the -i option with sed command. If you dont wish to delete the lines from the original source file you can redirect the output of the sed command to another file.
How do I remove the first 10 lines in Unix?
Remove first N lines of a file in place in unix command line
- Both sed -i and gawk v4. 1 -i -inplace options are basically creating temp file behind the scenes. …
- tail is multiple times faster for this task, than sed or awk . ( of course doesn’t fit for this question for real inplace)
How do you delete a specific line in a file Linux?
The syntax is <address><command> ; where <address> can be either a single line like 5 or a range of lines like 5,10 , and the command d deletes the given line or lines. The addresses can also be regular expressions, or the dollar sign $ indicating the last line of the file.
How do I delete a file?
- Open your phone’s Files app .
- Tap a file.
- Tap Delete Delete. If you don’t see the Delete icon, tap More. Delete .
Which method is used to delete a directory?
os. rmdir() removes a file or a directory. The shutil. rmtree() method will delete a directory and the files contained in it.
How can we delete all files in a directory Java?
Method 1: using delete() to delete files and empty folders
- Provide the path of a directory.
- Call user-defined method deleteDirectory() to delete all the files and subfolders.
How do I remove the last line in Unix?
So sed ‘$d’ file; sed ‘$d’ file will print out the contents of the file twice, minus the last line each time. The delete-the-last-two-lines equivalent of sed ‘$d’ file is sed ‘$d’ file | sed ‘$d’ . Yeah, that’s inelegant but of course it works.
How do you skip the first line while reading a file in Unix?
1 Answer. Use an extra read inside a compound command. This is more efficient than using a separate process to skip the first line, and prevents the while loop from running in a subshell (which might be important if you try to set any variables in the body of the loop).
How do I remove the first line from a csv file in Unix?
Here 1d is the command to execute:
- 1 => line where to act.
- d => delete.