Powershell file io example

For reading files efficiently, what are some functions or libraries we can use? 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:. 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?

You end up with an array of strings. This also passes each one down the pipe nicely. The -Raw parameter will bring the entire contents in as a multi-line string. This also performs faster because fewer objects are getting created. This is good for storing an object or basic structured data that can be imported later. The CSV format is comma separated values in a text file.

Excel is often the default viewer for CSV files. There are other ways to do it but this is by far the easiest. This is for objects with nested values or complex datatypes. The raw data will be a verbose serialized object in XML. The nice thing is that you can save a an object to the file and when you import it, you will get that object back. This serialized format is not intened for be viewd or edited directly.

Here is what the date. ConvertFrom-Json will convert it back into an object. These commands do not save or read from files on their own. You will have to turn to Get-Content and Set-Content for that. There is one important thing to note on this example. This may not be a problem but there is not an easy fix for it. Also note the use of the Get-Content -Raw in this example.

ConvertFrom-Json expects one string per object. You will notice that this is similar the original hashtable. This is why JSON is a popular format. It is easy to read, understand and edit if needed. I use this all the time for configuration files in my own projects.

All of those CmdLets are easy to work with. Other ideas? Richard Berg Richard Berg Add a comment. Active Oldest Votes. Very cool! Never seen this syntax. This is the same syntax used to access variables. There is a special interface on Providers to support this, but not all providers implement it. So that is really how you access variables in the variable provider. Sign up or log in Sign up using Google. Overwriting a file of the same name is not allowed.

Copy String, String, Boolean. Overwriting a file of the same name is allowed. Create String. Create String, Int Creates or overwrites a file in the specified path, specifying a buffer size. Create String, Int32, FileOptions. CreateSymbolicLink String, String. CreateText String. Decrypt String. Delete String. Encrypt String. Encrypts a file so that only the account used to encrypt the file can decrypt it.

Exists String. GetAccessControl String. GetAttributes String. GetCreationTime String. Returns the creation date and time of the specified file or directory. GetCreationTimeUtc String. GetLastAccessTime String. Returns the date and time the specified file or directory was last accessed. GetLastWriteTime String. Returns the date and time the specified file or directory was last written to. Move String, String.

Moves a specified file to a new location, providing the option to specify a new file name. Move String, String, Boolean. Open String, FileMode. Open String, FileStreamOptions. OpenRead String. OpenText String. OpenWrite String. ReadAllBytes String. Opens a binary file, reads the contents of the file into a byte array, and then closes the file. ReadAllLines String. Opens a text file, reads all lines of the file, and then closes the file.