I want to essentially keep the first comment section lines of a file and overwrite everything else. Currently this section is 27 lines long.

Each line begins with a # (think of it as a giant comment section).

What I want to do is keep the initial comment section, delete everything following the comment section, then append a new string to this file just below this comment section.

I found a way to hardcode it, but I think this is pretty ineffecient. I don't think it's best to hardcode in 27 as a literal.

The way I've handled it is:

                   $fileProc = Get-Content $someFile
                   
                   $keep = $fileProc[0..27]

                   $keep | Set-Content $someFile
                   
                   Add-Content $someFile "`n`n# Insert new string here"
                   Add-Content $someFile "`n EMPTY_PROCESS.EXE"

Is there a more efficient way to handle this?

Edit: Made some clarifications to the issue.

CodePudding user response：

You can use a switch statement to efficiently extract the section of comment lines at the start.

Set-Content out.txt -Value $(
  @(
    switch -Wildcard -File $someFile {
      '#*' { $_ }
      default { break } # End of comments section reached.
    }
  )   "`n`n# Insert new string here", "`n EMPTY_PROCESS.EXE"
)

Note:

• To be safe, the above writes to a new file, out.txt, but you can write directly back to $someFile, if desired.

• Wildcard expression #* assumes that each line in the comment section starts with #, with no preceding whitespace; if you need to account for preceding whitespace, use the -Regex switch in lieu of -Wildcard, and use regex '^\s*#' in lieu of '#*'

CodePudding user response：

Not sure about limiting it to first set of 27 or so lines but this should work.

First line below is to only keep the lines of file that start with '#'.

(Get-Content $somefile) | Where { $_ -match "^#" } | Set-Content $somefile

Add-Content $somefile "`n`nblah blah"
Add-Content $somefile "`nglug glug blug glug"

You can then use Add-Content for additional lines. Hope this helps :]