I have a little c# console program that outputs some text using Console.WriteLine. I then pipe this output into a textfile like:
c:myprogram > textfile.txt
However, the file is always an ansi text file, even when I start cmd with the /u switch.
cmd /? says about the /u switch:
/U Causes the output of internal
commands to a pipe or file to be Unicode
And it indeed makes a difference, when I do an
c:echo "foo" > text.txt
the text.txt is unicode (without BOM)
I wonder why piping the output of my console program into a new file does not create an unicode file likewise and how i could change that?
I just use Windows Power Shell (which produces a unicode file with correct BOM), but I'd still like to know how to do it with cmd.
Thanks!
The /U switch, as the documentation says, affects whether internal commands generate Unicode output. Your program is not one of cmd.exe's internal commands, so the /U option does not affect it.
To create a Unicode text file, you need to make sure your program is generating Unicode text.
Even that may not be enough, though. I came across this blog from Junfeng Zhang describing how to write Unicode text in a console program. It checks the file type of the standard output handle. For character files (a console or LPT port), it calls WriteFileW. For all other types of handles (including disk files and pipes), it converts the output string to the console's current code page. I'm afraid I don't know how that translates into .Net terms, though.
I had a look how mscorlib implements Console.WriteLine, and it seems to decide on which text output encoding to use based on a call to GetConsoleOutPutCP. So I'm guessing (but have not yet confimed) that the codepage returned is a differnt one for a PS console than for a cmd console so that my program indeed only outputs ansi when running from cmd.
Related
I want to run program in Powershell and write output to file with UTF-8 encoding.
However I can't write non-ascii characters properly.
I already read many similar questions on Stack overflow, but I still can't find answer.
I tried both PowerShell 5.1.19041.1023 and PowerShell Core 7.1.3, they differently encode output file, but content is broken in the same way.
I tried simple programs in Python and Golang:
(Please assume that I can't change source code of programs)
Python
print('Hello ąćęłńóśźż world')
Results:
python hello.py
Hello ąćęłńóśźż world
python hello.py > file1.txt
Hello ╣Šŕ│˝ˇťč┐ world
python hello.py | out-file -encoding utf8 file2.ext
Hello ╣Šŕ│˝ˇťč┐ world
On cmd:
python hello.py > file3.txt
Hello ���� world
Golang
package main
import "fmt"
func main() {
fmt.Printf("Hello ąćęłńóśźż world\n")
}
Results:
go run hello.go:
Hello ąćęłńóśźż world
go run hello.go > file4.txt
Hello ─ů─ç─Ö┼é┼ä├│┼Ť┼║┼╝ world
go run hello.go | out-file -encoding utf8 file5.txt
Hello ─ů─ç─Ö┼é┼ä├│┼Ť┼║┼╝ world
On cmd it works ok:
go run hello.go > file6.txt
Hello ąćęłńóśźż world
You should set the OutputEncoding property of the console first.
In PowerShell, enter this line before running your programs:
[Console]::OutputEncoding = [Text.Encoding]::Utf8
You can then use Out-File with your encoding type:
py hello.py | Out-File -Encoding UTF8 file2.ext
go run hello.go | Out-File -Encoding UTF8 file5.txt
Note: These character-encoding problems only plague PowerShell on Windows, in both editions. On Unix-like platforms, UTF-8 is consistently used.[1]
Quicksilver's answer is fundamentally correct:
It is the character encoding stored in [Console]::OutputEncoding that determines how PowerShell decodes text received from external programs[2] - and note that it invariably interprets such output as text (strings).
[Console]::OutputEncoding by default reflects a console's active code page, which itself defaults to the system's active OEM code page, such as 437 (CP437) on US-English systems.
The standard chcp program also reports the active OEM code page, and while it can in principle also be used to change it for the active console (e.g., chcp 65001), this does not work from inside PowerShell, due to .NET caching the encodings.
Therefore, you may have to (temporarily) set [Console]::OutputEncoding to match the actual character encoding used by a given external console program:
While many console programs respect the active console code page (in which case no workarounds are required), some do not, typically in order to provide full Unicode support. Note that you may not notice a problem until you programmatically process such a program's output (meaning: capturing in a variable, sending through the pipeline to another command, redirection to a file), because such a program may detect the case when its stdout is directly connected to the console and may then selectively use full Unicode support for display.
Notable CLIs that do not respect the active console code page:
Python exhibits nonstandard behavior in that it uses the active ANSI code page by default, i.e. the code page normally only used by non-Unicode GUI-subsystem applications.
However, you can use $env:PYTHONUTF8=1 before invoking Python scripts to instruct Python to use UTF-8 instead (which then applies to all Python calls made from the same process); in v3.7+, you can alternatively pass command-line option -X utf8 (case-sensitive) as a per-call opt-in.
Go and also Node.js invariably use UTF-8 encoding.
The following snippet shows how to set [Console]::OutputEncoding temporarily as needed:
# Save the original encoding.
$orig = [Console]::OutputEncoding
# Work with console programs that use UTF-8 encoding,
# such as Go and Node.js
[Console]::OutputEncoding = [System.Text.UTF8Encoding]::new()
# Piping to Write-Output is a dummy operation that forces
# decoding of the external program's output, so that encoding problems would show.
go run hello.go | Write-Output
# Work with console programs that use ANSI encoding, such as Python.
# As noted, the alternative is to configure Python to use UTF-8.
[Console]::OutputEncoding = [System.Text.Encoding]::GetEncoding([int] (Get-ItemPropertyValue HKLM:\SYSTEM\CurrentControlSet\Control\Nls\CodePage ACP))
python hello.py | Write-Output
# Restore the original encoding.
[Console]::OutputEncoding = $orig
Your own answer provides an effective alternative, but it comes with caveats:
Activating the Use Unicode UTF-8 for worldwide language support feature via Control Panel (or the equivalent registry settings) changes the code pages system-wide, which affects not only all console windows and console applications, but also legacy (non-Unicode) GUI-subsystem applications, given that both the OEM and the ANSI code pages are being set.
Notable side effects include:
Windows PowerShell's default behavior changes, because it uses the ANSI code page both to read source code and as the default encoding for the Get-Content and Set-Content cmdlets.
For instance, existing Windows PowerShell scripts that contain non-ASCII range characters such as é will then misbehave, unless they were saved as UTF-8 with a BOM (or as "Unicode", UTF-16LE, which always has a BOM).
By contrast, PowerShell (Core) v6+ consistently uses (BOM-less) UTF-8 to begin with.
Old console applications may break with 65001 (UTF-8) as the active OEM code page, as they may not be able to handle the variable-length encoding aspect of UTF-8 (a single character can be encoded by up to 4 bytes).
See this answer for more information.
[1] The cross-platform PowerShell (Core) v6+ edition uses (BOM-less) UTF-8 consistently. While it is possible to configure Unix terminals and thereby console (terminal) applications to use a character encoding other than UTF-8, doing so is rare these days - UTF-8 is almost universally used.
[2] By contrast, it is the $OutputEncoding preference variable that determines the encoding used for sending text to external programs, via the pipeline.
Solution is to enable Beta: Use Unicode UTF-8 for worldwide language support as described in What does "Beta: Use Unicode UTF-8 for worldwide language support" actually do?
Note: this solution may cause problems with legacy programs. Please read answer by mklement0 and answer by Quciksilver for details and alternative solutions.
Also I found explanation written by Ghisler helpful (source):
If you check this option, Windows will use codepage 65001 (Unicode
UTF-8) instead of the local codepage like 1252 (Western Latin1) for
all plain text files. The advantage is that text files created in e.g.
Russian locale can also be read in other locale like Western or
Central Europe. The downside is that ANSI-Only programs (most older
programs) will show garbage instead of accented characters.
Also Powershell before version 7.1 has a bug when this option is enabled. If you enable it , you may want to upgrade to version 7.1 or later.
I like this solution because it's enough to set it once and it's working. It brings consistent Unix-like UTF-8 behaviour to Windows. I hope I will not see any issues.
How to enable it:
Win+R → intl.cpl
Administrative tab
Click the Change system locale button
Enable Beta: Use Unicode UTF-8 for worldwide language support
Reboot
or alternatively via reg file:
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Nls\CodePage]
"ACP"="65001"
"OEMCP"="65001"
"MACCP"="65001"
I am a long-time Linux user and am used to a command like:
echo 'hello' > a.txt
creating a plaintext file simply containing 'hello'.
Now, if I use the same command in Windows PowerShell, the resulting file is claimed to be binary (by git). If I inspect the file in a text editor, the file contains the text but some weird excessive characters that look like a character encoding issue.
How am I supposed to use echo instead to make it behave in a completely "ordinary" plaintext way?
Docker version 18.03.1-ce, build 9ee9f40
I'm using powershell to build a big project on windows.
When issuing the command
docker save docker.elastic.co/kibana/kibana > deploy/kibana.docker
I'm getting an file 1.4Gb.
Same command run in CMD produces 799Mb image.
Same command run in bash produces 799Mb image.
CMD and Bash takes less than a minute to save an image, while Powershell takes about 10 minutes.
I did not manage to find any normal explanation of this phenomenon in docker or MS docs.
Right now the "solution" is
Write-Output "Saving images to files"
cmd /c .\deploy-hack.cmd
But I want to find the actual underlying reason for this.
PowerShell doesn't support outputting / passing raw byte streams through - any output from an external program such as docker is parsed line by line, into strings and the strings are then re-encoded on output to a file (if necessary).
It is the overhead of parsing, decoding and re-encoding that explains the performance degradation.
Windows PowerShell's > redirection operator produces UTF16-LE ("Unicode") files by default (whereas PowerShell Core uses UTF8), i.e., files that use (at least) 2 bytes per character. Therefore, it produces files that are twice the size of raw byte input[1], because each byte is interpreted as a character that receives a 2-byte representation in the output.
Your best bet is to use docker save with the -o / --output option to specify the output file (see the docs):
docker save docker.elastic.co/kibana/kibana -o deploy/kibana.docker
[1] Strictly speaking, how PowerShell interprets output from external programs depends on the value of [console]::OutputEncoding, which, if set to UTF8 (chcp 65001 on Windows), could situationally interpret multiple bytes as a single character. However, on Windows PowerShell the default is determined by the (legacy) system locale's OEM code page, which is always a single-byte encoding.
Trying to get an output through cmd with the list of folders and files inside a drive.
Some folders are written in cyrillic alphabet so I only get ??? symbols.
My command:
tree /f /a |clip
or
tree /f /a >output.txt
Result:
\---???????????
\---2017 - ????? ??????? ????
01. ?????.mp3
02. ? ???????.mp3
03. ????.mp3
04. ?????? ? ???.mp3
05. ?????.mp3
06. ???? ?????.mp3
07. ???????? ????.mp3
08. ??? ?? ?????.mp3
Cover.jpg
Any idea?
tree.com uses the native UTF-16 encoding when writing to the console, just like cmd.exe and powershell.exe. So at first you'd expect redirecting the output to a file or pipe to also use Unicode. But tree.com, like most command-line utilities, encodes output to a pipe or disk file using a legacy codepage. (Speaking of legacy, the ".com" in the filename here is historical. In 64-bit Windows it's a regular 64-bit executable, not 16-bit DOS code.)
When writing to a pipe or disk file, some programs hard code the system ANSI codepage (e.g. 1252 in Western Europe) or OEM codepage (e.g. 850 in Western Europe), while some use the console's current output codepage (if attached to a console), which defaults to OEM. The latter would be great because you can change the console's output codepage to UTF-8 via chcp.com 65001. Unfortunately tree.com uses the OEM codepage, with no option to use anything else.
cmd.exe, on the other hand, at least provides a /u option to output its built-in commands as UTF-16. So, if you don't really need tree-formatted output, you could simply use cmd's dir command. For example:
cmd /u /c "dir /s /b" | clip
If you do need tree-formatted output, one workaround would be to read the output from tree.com directly from a console screen buffer, which can be done relatively easily for up to 9,999 lines. But that's not generally practical.
Otherwise PowerShell is probably your best option. For example, you could modify the Show-Tree script to output files in addition to directories.
How can I write to parallel port through Windows XP command line?
Looking at your reply to Zoredache, your real problem is not output to the parallel port, that's trivial.
Your real problem is how to get a 0xff character on stdout. This is possible with a trivial .com executable which invokes the relevant soft interrupt, but to be honest it's probably easier to create a file with that single 0xff character in it and then just copy that to the printer:
> copy /b data.bin lpt1
Note the /b flag which tells copy that the file is a binary file.
Back in the DOS days we would frequently use a command like type filename.txt > lpt1 to print our text files.