Often we reach to a situation where we need to get top 10 or 100 lines of a file.
These commands are fairly simple in Unix shell programming and most of you must have used Head and Tail commands. Those commands work really fast and accurate.
Keeping these points in mind, I dig something and want to share will all of you.
How to use Head and Tail Commands in Powershell?
To get the top 10 lines -
Get-Content ".\file_test.txt" | select -First 10
To get the top 10 lines -
Get-Content ".\file_test.txt" | select -Last 10
Easy! This is power of Powershell !
Some more Examples:
Problem: Write a command to get 3rd line of a file.
Solution:
Get-Content ".\file_test.txt" | select -First 3 | select -Last 1
Problem: Write a command to skip 10 lines from top and display rest all lines of file.
Solution:
Get-Content ".\file_test.txt" | select -Skip 10
But this approach has one drawback, when file is so big, it takes a little more time to produce results.
To be able to read a big file, you can adjust Get-Content to read only few lines. As you saw, we were reading the complete file before that caused more memory consumption.
Enjoy Scripting!!
These commands are fairly simple in Unix shell programming and most of you must have used Head and Tail commands. Those commands work really fast and accurate.
Keeping these points in mind, I dig something and want to share will all of you.
How to use Head and Tail Commands in Powershell?
To get the top 10 lines -
Get-Content ".\file_test.txt" | select -First 10
To get the top 10 lines -
Get-Content ".\file_test.txt" | select -Last 10
Easy! This is power of Powershell !
Some more Examples:
Problem: Write a command to get 3rd line of a file.
Solution:
Get-Content ".\file_test.txt" | select -First 3 | select -Last 1
Problem: Write a command to skip 10 lines from top and display rest all lines of file.
Solution:
Get-Content ".\file_test.txt" | select -Skip 10
But this approach has one drawback, when file is so big, it takes a little more time to produce results.
To be able to read a big file, you can adjust Get-Content to read only few lines. As you saw, we were reading the complete file before that caused more memory consumption.
Enjoy Scripting!!
This comment has been removed by a blog administrator.
ReplyDeleteEven better. But still last 5 lines might take longer time for large files.
ReplyDeleteto get last lines of large files use:
ReplyDeleteget-content $myFile -tail 5
- tail rockz thx !
ReplyDeleteTop 5: get-content $targetFile -totalcount 5
ReplyDeleteDon't pipe if you don't have to!
These are the examples for extracting the data from a file, but i want extract data from command output, so how can i achieve this?
ReplyDeleteSimply put your data into a variable, then pipe that into the select command.
DeleteFor example:
$data = get-process
Then $data | select -last 10
Is there any way to search between two occurrences of a word.
ReplyDeleteI am trying to pull the last few lines from huge files and this seems to take forever... I'm still waiting (minutes) for the first attempt to work. I would love the -tail option but it does not seem to work in my powershell. At least the pipe to select works:
ReplyDeletePS C:\temp> Get-Content .\remapp_printers.txt | select -last 3
\\mhmv-qs-100v\277R100HPCLJ4525DN - 1a
\mhmv-qs-10 = plk-fs-01 - 1b
New default printer = \\mhmv-qs-100v\15 PCL6 - 12/5/2016 - 6
PS C:\temp> Get-Content .\remapp_printers.txt -tail 3
Get-Content : A parameter cannot be found that matches parameter name 'tail'.
At line:1 char:40
+ Get-Content .\remapp_printers.txt -tail <<<< 3
+ CategoryInfo : InvalidArgument: (:) [Get-Content], ParameterBin
dingException
+ FullyQualifiedErrorId : NamedParameterNotFound,Microsoft.PowerShell.Comm
ands.GetContentCommand
This comment has been removed by the author.
DeleteHi Kevin and All,
ReplyDeleteI was searching for some Live online help for Powershell.
However i didn't find any suitable online live group
So, i thought to create a Skype Group.
Here we can help each other to solve any Powershell issue or puzzle.
Please join me on https://join.skype.com/yY056Inw1A8q
Let's help each other. we really appreciate your help
Regards,
Param
Thanks for sharing such important information which is very useful .I really appreciate your way of work.
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Thank you for this information of displaying top n lines or last n lines of a file. If you want to get the top 10s news all over the world then, visit The Youth.
ReplyDelete