Windows – the Windows equivalent of the Unix command cat

catunixwindows

I want to do exactly what unix "cat" does, but on my PC. Is there a simple equivalent command for the Windows command line?

Specifically I want to create a file from all the files of a given type in a folder

In Unix:

cat *fna >all_fna_files.fna

(which joins all the ".fna" text files into one big text file)

Best Answer

`type`

It works across command.com, cmd, and PowerShell (though in the latter it's an alias for Get-Content, so is cat, so you could use either). From the Wikipedia article (emphasis mine):

In computing, type is a command in various VMS. AmigaDOS, CP/M, DOS, OS/2 and Microsoft Windows command line interpreters (shells) such as COMMAND.COM, cmd.exe, 4DOS/4NT and Windows PowerShell. It is used to display the contents of specified files. It is analogous to the Unix cat command.

C:\>echo hi > a.txt
C:\>echo bye > b.txt
C:\>type a.txt b.txt > c.txt
C:\>type c.txt
hi
bye

edit

You get the error after su'ing to another user because that user doesn't have appropriate permissions to connect to your X server. X uses a permission checking protocol known as MIT magic cookie, which works by creating a random string to use as a password. That password is stored in the file $XAUTHORITY, or ~/.Xauthority if the environment variable is not set. It is manipulated by the xauth tool. For example,

$ xauth list
…
Feynman/unix:0  MIT-MAGIC-COOKIE-1  <<redacted>>
…

I'm not sure what you're doing the su for, but:

if it's so you can read the file, then just run the cat as the other user, and pipe the output of su to xclip. This way, xclip runs as your user, and works.
if you're trying to set the clipboard for another user's X session, then you'll need to set $DISPLAY to that user's display, and $XAUTHORITY to that user's X authority file. Look into ConsoleKit (if you're using it) and /var/lib/gdm (if you're using gdm) to find said things.

If none of the above, then you'll have to use xauth to set up the authorization, and keep in mind that anything connecting to your X server can do all sorts of evil, such as watch all your keystrokes.

PS: The $DISPLAY refers to which X server they're logged in to. Unless you've set up multiple servers running (so multiple users may log in at once), it will be the same for all users.

Windows – PowerShell equivalent to the Unix `which` command

This was asked and answered on Stack Overflow: Equivalent of *Nix 'which' command in PowerShell?

The very first alias I made once I started customizing my profile in PowerShell was 'which'.

New-Alias which get-command

To add this to your profile, type this:

"`nNew-Alias which get-command" | add-content $profile

The `n at the start of the last line is to ensure it will start as a new line.

Best Answer

type

Related Solutions

Ubuntu – Error in the command “cat file | xclip”

edit

Windows – PowerShell equivalent to the Unix `which` command

Related Question

`type`