We only call these methods on the first two lines by only getting the lines less than line three:. For parsing data, we can use our string methods on each line of the file — or on a specific line of the file — on each iteration of the loop. Finally, we want to be able to get a specific line from the file — we can get the first and last line of the file by using Get-Content.
No action is necessary. Also, the dispose method does end the object, as we can check by calling the method from the command line in PowerShell ISE and it will return nothing we could also check within the function and get the same result :.
For custom performance, StreamReader offers more potential, as we can read each line of data and apply our additional functions as we need. Just be careful if the files tend to grow in time. Computers are much more efficient and did you know humans actually have bad eyesight compared with other animals? I digress. Head over to adamtheautomator.
Trang web. Home News Reading file data with powershell. Overview For reading data from files, we generally want to focus on three major functions for completing these tasks along with some examples listed next to them of these in practice: How to read an entire file, part of a file or skip around in a file.
We may face a situation where we want to read every line except the first and last. How to read a file by using few system resources. Besides Where-Object, you can also use match and regex operators to find the exact text you want.
Get-Content is a highly versatile cmdlet that comes loaded with many options. Here are some things you can do with it. You may want to know the number of lines available in the file, so you can parse it accordingly.
The code for that is:. Earlier, we saw how to choose the first few or last few lines using the Select-Object cmdlet. You can also get the same results using some of the built-in methods of Get-Content. For that, you can add the Wait parameter, like this:. This command will continuously monitor the log file for the new lines that are getting added to it and will display the same to you.
Thus, these are some of the different ways to read a text file in PowerShell. Do let us know if you know more ways to read the contents of a file in PowerShell. Home » Tutorials » How to read a text file in PowerShell quickly and easily. Lavanya Rathnam is a professional writer of tech and financial blogs. Creative thinker, out of the boxer, content builder and tenacious researcher who specializes in explaining complex ideas to different audiences.
The above applies to most situations involved with parsing data from files. Get-Content outputs the entire file of logging.
This begins to cost us performance, as we deal with larger file sizes. We can select a part of the file by treating our variable object being another name like a SQL query where we select some of the files instead of all of it. In the code below, we select the first five lines of the file, rather than the entire file:. We can also use the same function to get the last five lines of the file, using a similar syntax:.
This makes Get-Content a great basic reader for file data. As we see in the output, we can read all the data from the file like with Get-Content using the ReadToEnd method; how do we read each line of data? Included in the StreamReader class is the ReadLine method and if we called it instead of ReadToEnd , we would get the first line of our files data:.
The ReadLine method reads the current line of the file, which in this case is the first line. Since we told the StreamReader to read the line, it read the first line of the file and stopped. The reason for this is that the ReadLine method only reads the current line in this case, line one. We must keep reading the file until we reach the end of the file.
0コメント