Im making a bat-file for windows that will run a simulation.
It will then look at the result in the console and search for the string "win%".
Ftm I can find anything including win but that gives me alot of unnessesary data.
This is what I got now:
command | findstr win >> file.txt
This gives me alot of unnessesary data.
I want to find:
command | findstr win% >> file.txt
But this dosent work at all....
How can I find the strings including "%"?
Br
Based on your question tags, your command appears within a batch script.
Percent literals must be escaped as %% within a batch script.
command | findstr win%% >> file.txt
The above will always work because your search string contains only one percent.
Note that each side of the pipe is executed in its own cmd.exe process using command line context (not batch). This could lead to a problem, depending on your search string and the current defined variables.
Suppose you wanted to search for win%lose%. The following might work:
command | findstr win%%lose%% >>file.txt
It works as long as there is no variable named lose in the environment. Since the FINDSTR command executes in a command line context, the %lose% string is preserved if lose is not defined.
But if lose is defined, then %lose% is expanded into the value and you get the wrong search. This could be solved by introducing a disappearing caret into the expression. A string like %^lose% will not expand a variable named lose. The variable expansion will include the caret as part of the name, not find anything, and leave the string intact. Afterwards, the normal escape phase will "escape" the l into itself, and the caret disappears. Now this would fail if a variable named ^lose is defined, but that is highly unlikely.
But the command is within a batch script, so the caret must be escaped.
command | findstr win%%^^lose%% >> file.txt
It is easier to simply enclose the string in quotes so you don't need to escape the caret.
command | findstr "win%%^lose%%" >> file.txt
Related
I need to pass a password with special characters from powershell script automation.ps1 to batch script batch_script.bat which pipes it to main.py. Piping from batch_script.bat to main.py works fine, that is authentication succeeds. However, when I run the entire procedure described above, authentication fails, but echoing the password shows the correct password string.
My guess is that there are issues with special characters. What is a safe way to pass these strings?
Background
I want to automate the daily download from some external source via a Python script main.py. This process requires a password. So I wrote a batch_script.bat which pipes the password to the Python script when prompted for it. However, I don't want to store the password as plain text in the batch script, so I encrypted the password and wrote another layer automation.ps1 which decrypts the password and passes it as plain text to batch_script.bat.
automation.ps1
# get password
$securePassword = Get-Content "<file_path>" | ConvertTo-SecureString
$credentials = New-Object System.Management.Automation.PsCredential("<user_name>",$securePassword)
$unsecurePassword = ($credentials).GetNetworkCredential().Password
# call script
$script = "<path>\batch_script.bat"
$args = #("`"<user name>`"","`"$unsecurePassword`"")
start-process $script $args
batch_script.bat
(I am aware that in this example I discard the passed username, just wanted to preserve the fact that I pass multiple arguments in case there is any relevance to it)
#echo off
SET username=%~1
SET password=%~2
echo(%password%|python main.py
With following, all special characters should be handled very well. If any character required to be escaped, check this
$pass could be any string but check for special characters of powershell
$pass="%^&<>|'\``,;=(\)![]\/";
# Wait till it ends with -Wait when using -NoNewWindow.
# It may be comprehensible to use `" instead of "" to denote we are enclosing string in quotes.
(thanks #mklement0 for elaboration).
start-process -Wait -NoNewWindow .\script.cmd "`"$pass`""
script.cmd
setlocal
rem Remove Double quotes
set "arg=%~1"
rem Test result with base64 encoding
echo|set/p="%arg%"|openssl base64
rem echo is used with set/p to prevent trailing new line.
echo|set/p="%arg%"|python main.py
rem Test with following, argument is in double quotes
rem script "%^&<>|'\`,;=(\)![]\/"
rem Expected result
rem %^&<>|'\`,;=(\)![]\/
tl;dr:
Unless you specifically need the batch file to run in a new window, avoid Start-Process (whose built-in aliases are start and saps), and invoke the batch file directly.
To avoid problems with special characters in $unsecurePassword, do not pass it as an argument, pass it via stdin (the standard input stream), which your batch file will pass through to your python script:
automation.ps1:
# ...
$script = "<path>\batch_script.bat"
# Pass the password via *stdin*
$unsecurePassword | & $script 'userName'
Note: It is the $OutputEncoding preference variable that controls what character encoding PowerShell uses for sending text to an external program's stdin. In Windows PowerShell, that variable defaults to ASCII(!) encoding, meaning that any characters outside the 7-bit ASCII-range of Unicode characters, such as accented characters, are unsupported (they turn to literal ?); fortunately, PowerShell [Core] v6+ now defaults to UTF-8. Assign the required encoding to $OutputEncoding as needed.
batch_script.bat:
#echo off
SET username=%~1
REM The batch file will pass its own stdin input through to Python.
python main.py
Read on for background information.
Invoking a batch file from PowerShell:
Unless you truly need to launch a batch file in a new window, the best approach is to invoke it directly from PowerShell; that way, it runs:
in the same console window, synchronously.
with its output streams connected to PowerShell's (which allows you to capture or redirect the output).
Because your batch-file path is stored in a variable, direct invocation requires use of &, the call operator:
# Note: The " chars. around $unsecurePassword are only needed if the variable
# value contains cmd.exe metacharacters - see next section.
& $script 'userA' `"$unsecurePassword`"
Start-Process is usually the wrong tool for invoking console applications, batch files, and other console-based scripts; see this answer for more information.
If you do need the batch file to run in a new window (which is only an option on Windows), use Start-Process as follows (the command will execute asynchronously, unless you also pass -Wait):
# The string with the arguments to pass is implicitly bound
# to the -ArgumentList parameter. Use only " for embedded quoting.
Start-Process $script "userA `"$unsecurePassword`""
Note: While the (implied) -ArgumentList (-Args) parameter is array-valued ([string[]]) and passing the arguments individually is arguably the cleaner approach, this generally does not work properly, due to a longstanding bug that probably won't get fixed; for instance,
Start-Process foo.exe -Args 'one', 'two (2)' passes 3 arguments rather than 2; that is, it passes single string 'two (2)' as two arguments - see this GitHub issue.
Therefore, it is ultimately simpler and more predictable to pass a single argument with embedded quoting to -ArgumentList, but be sure to use only " (not ') for embedded quoting:
Start-Process foo.exe -Args "one `"two (2)`""
Passing arguments robustly to cmd.exe / batch files:
Note:
The limitations of cmd.exe (the legacy command processor that interprets batch files) prevent fully robust solutions; notably, you cannot prevent the interpretation of tokens such as %foo% as environment-variable references when you call a batch file from PowerShell (at least not without altering the argument to %foo^%, which will retain the ^).
In your specific case, since you're trying to echo an argument unquoted, embedded double quotes (") in such an argument - which need to be escaped as "" - aren't properly supported: they are passed through as "".
Passing an unquoted argument to cmd.exe / a batch file breaks, if that argument contains one of cmd.exe's metacharacters, i.e., characters with special syntactic meaning; in this context, they are: & | < > ^ "
The solution is to enclose the argument in double quotes ("..."), with the added need to double " chars. that are embedded (a part of the value).
PowerShell, after performing its own parsing of the command line (notably evaluating variable references and expressions), constructs the command line that is ultimately used to invoke the external target program, behind the scenes.
However, it only automatically double-quotes an argument if it contains spaces, not if it only contains cmd.exe metacharacters; e.g., a variable with verbatim string content two (2) is passed double-quoted - $val = 'two 2'; .\foo.bat $val results in command line .\foo.bat "two 2" - whereas string content a&b is not - $val = 'a&b'.\foo.bat $val results in .\foo.bat a&b - which breaks.
The solution - as shown in your question - is to enclose the variable reference in literal, embedded " characters, because such a "pre-quoted" value instructs PowerShell to pass the value as-is:
$val = 'a&b'; .\foo.bat `"$val`" results in .\foo.bat "a&b"
Note: .\foo.bat "`"$val`"" has the same effect; I'm taking advantage of the fact that PowerShell in argument (parsing) mode (generally) implicitly treats arguments as if they were double-quoted; in expression (parsing) mode, such as in the array-construction statement in the question (#(..., ...)), you do need the "`"$val`"" form.
The problem with your specific batch file:
A properly "..."-enclosed argument (with any embedded " chars. escaped as "") is properly seen as a parameter (e.g., %1) inside a batch file.
However, it is seen with the enclosing double quotes and with any doubled embedded " chars.
If you were to pass this parameter to the target program (python in this case) as an argument, everything would work as expected.
However, since you're passing the value via stdin using echo, you need to strip the enclosing double quotes so that they're not passed as part of the value, which is what your batch file attempts (e.g., %~2)
However, passing the stripped value causes the echo command to break.
There is no good solution to this problem with echo, short of performing cumbersome explicit ^-escaping (^ being cmd.exe's escape character):
$escapedUnsecurePassword = $unsecurePassword -replace '[&|<>^]' -replace '"', '""'
& $script 'userA' `"$escapedUnsecurePassword`"
That alone still isn't enough, however - your batch_script.bat file needs a modification too:
Because the assignment itself in your SET password=%~2 command isn't protected with double quotes, it breaks with values that contain metacharacters; somewhat paradoxically, you must use the form SET "password=%~2" in order to safely strip the embedded enclosing " chars.:
#echo off
REM Strip the enclosing "..." from the arguments (%~<n>)
REM !! The *assignment itself* must be in "..." so that
REM !! it does not break if the value has cmd.exe metacharacters.
set "username=%~1"
set "password=%~2"
echo(%password%|python main.py
Note that that will work as intended for all metacharacters except the - of necessity doubled - embedded ", which are passed through as "".
However, there is a workaround for echoing a string with metacharacters unquoted, as also demonstrated in subcoder's helpful answer:
If you define batch_script.bat as follows:
#echo off
set "username=%~1"
REM Do NOT strip quotes from the password argument
set password=%2
REM Using a trick with set /p, echo the password unquoted.
REM Note: Put the "|" directly after the ":" to avoid trailing spaces.
<NUL set /p=%password% & echo:|python main.py
The workaround repurposes set's /p option, which accepts a prompt message to print when interactively prompting the user for a value and prints the message without quotes; the actual interactive prompt is suppressed via <NUL, so that only the message is printed.
echo: prints a newline (line break), which is necessary, because the set /p command prints its message without a trailing newline (if you don't want to send a newline, simply omit & echo:).
Caveat: In addition to the problem with embedded "" applying here too, this workaround has a side effect: it trims leading whitespace; e.g., " foo " results in output foo (only trailing whitespace is preserved); however, given that arguments with leading whitespace are rare, this may not matter in practice.
Given how cumbersome / obscure the above approaches are, the stdin-based approach shown at the top is preferable.
You pass arguments to batch files in powershell using the -argumentlist switch of start/saps. For you you could use:
saps "$script" -argumentlist $args
But I would suggest first breaking $args up as it may not work since to pass arguments, you usually want to pass the arguments one at a time like:
saps "$script" -argumentlist "1","2","3"
Passing $args will work most of the time, but there are some cases where where it won't work. Most of the time you are fine though
I've got a batch script (app1.bat) calling another batch script (app2.bat) which itself calls a program in windows (program.exe).
app2.bat calls program.exe with a parameter after a flag in this way:
program.exe -f Parameter with whitespaces coming into the program
What I want to do is to pass the phrase that comes to program.exe from app1.bat into app2.bat but i don't know how to properly handle the doublequotes. Currently I am passing the phrase from app1.bat to app2.bat in double quotes and inside an app2.bat (prior to executing program.exe) I get rid of the quotes like that:
inside app1.bat
call app2.bat "Parameter with whitespaces coming into the program"
inside app2.bat
set old_phrase=%1%
set new_phrase=%old_phrase:"=%
program.exe -f %new_phrase%
old_phrase is
"Parameter with whitespaces coming into the program"
and new_phrase I end up with is
Parameter with whitespaces coming into the program
Is there any standard way to handle such a situation (being passing a string to an external program which expects a tring without quotes and being ok with whitespaces, whereas batch does not allow for no-quotes-and-whitespaces strings)
When you execute call /? from cmd to launch the help you will see quite a bit around expansion of %n
The first one states:
%~1 - expands %1 removing any surrounding quotes (")
You can therefore dump all the other set commands and simply run this in your batch file:
program.exe -f %~1
I'm in the unfortunate position to be forced to invoke a program via echo <input> | program.exe. Of course, I wondered how to escape <input> and found:
How does the Windows Command Interpreter (CMD.EXE) parse scripts?
Escape angle brackets in a Windows command prompt
In essence, it seems sufficient to escape all special chars with ^. Out of curiosity I still would like to know, why echo ingores double-quote escaping in the first place:
C:\>echo "foo"
"foo"
C:\>
Is there any normative reference?
Bonus question: How to echo the strings on and off with the echo command?
Edit: I just found this. I states that only |<> need to be escaped. However, expansion like %FOO% still work.
Special characters like ^, &, (, ), <, >, %, ! and " may cause problems with echo, also when trying to echo a string into a pipe; odd numbers of " are particularly difficult to handle.
Building escape sequences can be very complicated particularly with pipes, because such initiates new cmd instances for either side, so multi-escaping might become necessary.
The only reliable way to pipe the output of echo into a program is to use a variable holding the string to return and to apply delayed expansion, but within the left side of the pipe, like this:
cmd /V /C echo(^^!VARIABLE^^!| program.exe
Note the double-escaping of ! like ^^!, which makes this code even work when delayed expansion is also enabled in the parent cmd instance. There must not be a SPACE in front of the |, because this was echoed too otherwise. Note that echo terminates the output by a line-break.
Here's a simple .bat file that shows the first three arguments with which the bat file is executed:
#echo 1: %1
#echo 2: %2
#echo 3: %3
When I execute the bat file like so
c:\> x:\show_parameters.bat "foo bar" baz "one two three"
the output is
1: "foo bar"
2: baz
3: "one two three"
I was surprised, because I didn't expect the double quotes to be passed as part of the arguments.
When I use a Perl script to show the values of the parameters
my $arg_cnt = 1;
for my $arg (#ARGV) {
printf "%2d: %s\n", $arg_cnt, $arg;
$arg_cnt++;
}
and execute the script like so
c:\> x:\show_parameter.pl "foo bar" baz "one two three"
it prints
1: foo bar
2: baz
3: one two three
that is, without any double quotes. This is the, imho, expected behaviour for the bat variant.
So, Why are the arguments passed differently to the bat file?
TL;DR: It depends on the shell implementation. On windows, the cmd console quoting uses different rules from the bash shell. source
I believe you're looking for:
#echo 1: %~1
#echo 2: %~2
#echo 3: %~3
See the documentation.
The Tilde character has special "modifier" meaning with batch parameters. If you think about it, Perl and batch are two different languages, and when a program is sent parameters, think of it like it's passed a query string, except it's upto the language to decide how to parse it. Really what you pass to the program is one-long parameter but the program splits on spaces while keeping in mind quotes and escaping.
You can also see #echo 0: %0 will show you the program in quotes while #echo 0: %~0 removes the double quotes.
To see the full line of "arguments" passed to the script, without being parsed, you'd do:
#echo *: %*
As you can see, the script is really passed one long argument and has to be parsed first, keeping spaces and quotes, and escape characters such as ^ in mind, in order to create the concept of multiple "arguments".
In terms of Perl's behavior, my guess is that Perl does this automagically for you when populating ARGV. Could check its source code if you're interested in the logic Perl is using.
Edit:
After playing with it for a while, I'm starting to think this is beyond Perl's control. I'm noticing the same behavior with PHP as well when testing print_r($argv); from commandline and it also loses its quotes.
You can see Perl is getting sent the parameters with quotes by running:
use Win32::API;
my $GetCommandLine = Win32::API->new('kernel32',
'GetCommandLine', [ ] , 'P' );
$cmdline = $GetCommandLine->Call();
print $cmdline;
But then you'd need to parse that if you wanted just the parameters and not the full command line command.
There's a question posted here exactly like yours:
http://www.nntp.perl.org/group/perl.beginners/2002/07/msg29597.html
To paraphrasing Peter Scott's answer there on the 2nd page: the shell does the whitespace splitting and dequoting before the program sees the arguments and it makes no difference what language the program is written in. So you'll have to find a workaround.
The answer is pretty consistent that it's a shell issue the more I research it.
For example even in Python, it's the same issue.
So why does batch give different results? It depends on the shell implementation. On windows, the cmd console quoting uses different rules from the bash shell.
consider
call :somesubroutine %*
Without the quotes, somesubroutine would see 6 arguments. With its sees 3.
Really a matter of definition, but batch seems to tell the truth here.
Consider also what happens with
x:\show_parameters.bat "foo bar" "" "one two three"
The Windows command prompt (cmd.exe) has an optional /s parameter, which modifies the behavior of /c (run a particular command and then exit) or /k (run a particular command and then show a shell prompt). This /s parameter evidently has something to do with some arcane quote handling.
The docs are confusing, but as far as I can tell, when you do cmd /csomething, and the something contains quotation marks, then by default cmd will sometimes strip off those quotes, and /s tells it to leave them alone.
What I don't understand is when the quote removal would break anything, because that's the only time /s ("suppress the default quote-removal behavior") would be necessary. It only removes quotes under a certain arcane set of conditions, and one of those conditions is that the first character after the /c must be a quotation mark. So it's not removing quotes around arguments; it's either removing quotes around the path to the EXE you're running, or around the entire command line (or possibly around the first half of the command line, which would be bizarre).
If the path to the EXE is quoted, e.g. cmd /c "c:\tools\foo.exe" arg1 arg2, then quotes are unnecessary, and if cmd wants to remove them, fine. (It won't remove them if the path has a space in the name -- that's another of the arcane rules.) I can't imagine any reason to suppress the quote removal, so /s seems unnecessary.
If the entire command line is quoted, e.g. cmd /c "foo.exe arg1 arg2", then it seems like quote removal would be a necessity, since there's no EXE named foo.exe arg1 arg2 on the system; so it seems like opting out of quote removal using /s would actually break things. (In actual fact, however, it does not break things: cmd /s /c "foo.exe arg1 arg2" works just fine.)
Is there some subtlety to /s that's eluding me? When would it ever be necessary? When would it even make any difference?
Cmd /S is very useful as it saves you having to worry about "quoting quotes". Recall that the /C argument means "execute this command as if I had typed it at the prompt, then quit".
So if you have a complicated command which you want to pass to CMD.exe you either have to remember CMD's argument quoting rules, and properly escape all of the quotes, or use /S, which triggers a special non-parsing rule of "Strip first and last " and treat all other characters as the command to execute unchanged".
You would use it where you want to take advantage of the capabilities of the CMD shell, rather than directly calling another program. For example environment variable expansion, output or input redirection, or using CMD.exe built-ins.
Example:
Use a shell built-in: This executes as-if you had typed DEL /Q/S "%TMP%\TestFile" at the prompt:
CMD.exe /S /C " DEL /Q/S "%TMP%\TestFile" "
This executes SomeCommand.exe redirecting standard output to a temp file and standard error to the same place:
CMD.exe /S /C " "%UserProfile%\SomeCommand.exe" > "%TMP%\TestOutput.txt" 2>&1 "
So what does /S give you extra? Mainly it saves you from having to worry about quoting the quotes. It also helps where you are unsure whether for example an environtment variable contains quote characters. Just say /S and put an extra quote at the beginning and end.
Vaguely Related: $* in Bourne Shell.
Some background
Recall that the list of arguments to main() is a C-ism and Unix-ism. The Unix/Linux shell (e.g. Bourne Shell etc) interprets the command line, un-quotes the arguments, expands wildcards like * to lists of files, and passes a list of arguments to the called program.
So if you say:
$ vi *.txt
The vi command sees for example these arguments:
vi
a.txt
b.txt
c.txt
d.txt
This is because unix/linux operates internally on the basis of "list of arguments".
Windows, which derives ultimately from CP/M and VAX, does not use this system internally. To the operating system, the command line is just a single string of characters. It is the responsibility of the called program to interpret the command line, expand file globs (* etc) and deal with unquoting quoted arguments.
So the arguments expected by C, have to be hacked up by the C runtime library. The operating system only supplies a single string with the arguments in, and if your language is not C (or even if it is) it may not be interpreted as space-separated arguments quoted according to shell rules, but as something completely different.
Here's an example of how it can make a difference.
Suppose you have two executables: c:\Program.exe and c:\Program Files\foo.exe.
If you say
cmd /c "c:\Program Files\foo"
you'll run foo.exe (with no arguments) whereas if you say
cmd /s /c "c:\Program Files\foo"
you'll run Program.exe with Files\foo as the argument.
(Oddly enough, in the first example, if foo.exe didn't exist, Program.exe would run instead.)
Addendum: if you were to type
c:\Program Files\foo
at the command prompt, you would run Program.exe (as happens with cmd /s /c) rather than foo.exe (as happens with just cmd /c). So one reason for using /s would be if you want to make sure a command is parsed in exactly the same way as if it were being typed at the command prompt. This is probably more likely to be desirable in the scenario in the question Michael Burr linked to, where cmd.exe is being launched by CreateProcess rather than from a batch file or the command line itself..
That is, if you say
CreateProcess("cmd.exe", "cmd /s /c \"" MY_COMMAND "\"", ...)
then the string MY_COMMAND will be parsed exactly as if it were typed at the command prompt. If you're taking command-line input from the user, or if you're a library processing a command line provided by an application, that's probably a good idea. For example, the C runtime library system() function might be implemented in this way.
In all but one specific case, the /S won't actually make any difference.
The help for cmd.exe is accurate, if a bit complicated:
If /C or /K is specified, then the remainder of the command line after
the switch is processed as a command line, where the following logic is
used to process quote (") characters:
If all of the following conditions are met, then quote characters
on the command line are preserved:
no /S switch
exactly two quote characters
no special characters between the two quote characters,
where special is one of: &<>()#^|
there are one or more whitespace characters between the
two quote characters
the string between the two quote characters is the name
of an executable file.
Otherwise, old behavior is to see if the first character is
a quote character and if so, strip the leading character and
remove the last quote character on the command line, preserving
any text after the last quote character.
I'd summarize as follows:
Normal behavior:
If the rest of the command line after /K or /C starts with a quote, both that quote and the final quote are removed. (See exception below.) Other than that, no quotes are removed.
Exception:
If the rest of the command line after /K or /C starts with a quote, followed by the name of an executable file, followed by another quote, AND if those are the only two quotes, AND if the file name contains spaces but contains no special characters, then the quotes are not removed (even though they normally would have been removed according to the rule above).
The only effect of /S is to override this one exception, so that the two quote characters are still removed in that case.
If you always use /S, you can forget about the exception and just remember the "normal" case. The downside is that cmd.exe /S /C "file name with spaces.exe" argument1 won't work without adding an extra set of quotes, whereas without /S it would have worked... until you decide to replace argument1 with "argument1".