I have the following sample string:
'-Dparam="x" -f hello-world.txt bye1.txt foo_bar.txt -Dparam2="y"'
I am trying to use RegEx (PowerShell, .NET flavor) to extract the filenames hello-world.txt, bye1.txt, and foo_bar.txt.
The real use case could have any number of -D parameters, and the -f <filenames> argument could appear in any position between these other parameters. I can't easily use something like split to extract it as the delimiter positioning could change, so I thought RegEx might be a good proposition here.
My attempt is something like this in PowerShell (can be opened on any Windows system and copy pasted into it):
'-Dparam="x" -f hello-world.txt bye1.txt foo_bar.txt -Dparam2="y"' -replace '^.* -f ([a-zA-Z0-9_.\s-]+).*$','$1'
Desired output:
hello-world.txt bye1.txt foo_bar.txt
My problem is that I either only take hello-world.txt, or I get hello-world.txt all the way to the end of the string or next = symbol (as in the example above).
I am having trouble expressing that \s is allowed, since I need to capture multiple space-delimited filenames, but that the combination of \s-[a-zA-Z] is not allowed, as that indicates the start of the next argument.
Related
I'm looking for a regsub example that does the following:
123tcl456TCL789 => 123!tcl!456!TCL!789
This is an Tcl example => This is an !Tcl! example
Yes, I could use string first to find a position and mash things but I saw in past a regsub command that does what I want but I can't recall. What would be the regsub command that allows that? I would guess regsub -all -nocase is a start.
I am bad at regsub and regexps. I wonder if there is a site or tool/script that we can supply a string, the final result and then we get the regsub form.
You're looking at the right tool, but there are various options, depending on exactly what the conditions are when faced with other text. Here's one that wraps each occurrence of "Tcl" (any capitalisation) with exclamation marks:
set inputString "123tcl456TCL789"
set replaced [regsub -all -nocase {tcl} $inputString {!&!}]
puts $replaced
That's using a very simple regular expression with the -nocase option, and the replacement means "put ! on either side of the substring matched".
Another (more generally applicable... perhaps) might be to put ! after any letter or number sequence that is followed by a number or letter.
set replaced [regsub -all {[A-Za-z]+(?=[0-9])|[0-9]+(?=[A-Za-z])} $inputString {&!}]
Note that doing things correctly typically requires understanding the real input data fairly well. For example, whether the numbers include floating point numbers in scientific notation, or whether the substrings to delimit are of fixed length.
Problem
I am working on a script that has a user provide a specific IP address and I want to mask this IP in some fashion so that it isn't stored in the logs. My problem is, that I can easily do this when I know what the first three values of the IP typically are; however, I want to avoid storing/hard coding those values into the code to if at all possible. I also want to be able to replace the values even if the first three are unknown to me.
Examples:
10.11.12.50 would display as XX.XX.XX.50
10.12.11.23 would also display as XX.XX.XX.23
I have looked up partial string replacements, but none of the questions or problems that I found came close to doing this. I have tried doing things like:
# This ended up replacing all of the numbers
$tempString = $str -replace '[0-9]', 'X'
I know that I am partway there, but I aiming to only replace only the first 3 sets of digits so, basically every digit that is before a '.', but I haven't been able to achieve this.
Question
Is what I'm trying to do possible to achieve with PowerShell? Is there a best practice way of achieving this?
Here's an example of how you can accomplish this:
Get-Content 'File.txt' |
ForEach-Object { $_ = $_ -replace '\d{1,3}\.\d{1,3}\.\d{1,3}','xx.xx.xx' }
This example matches a digit 1-3 times, a literal period, and continues that pattern so it'll capture anything from 0-999.0-999.0-999 and replace with xx.xx.xx
TheIncorrigible1's helpful answer is an exact way of solving the problem (replacement only happens if 3 consecutive .-separated groups of 1-3 digits are matched.)
A looser, but shorter solution that replaces everything but the last .-prefixed digit group:
PS> '10.11.12.50' -replace '.+(?=\.\d+$)', 'XX.XX.XX'
XX.XX.XX.50
(?=\.\d+$) is a (positive) lookahead assertion ((?=...)) that matches the enclosed subexpression (a literal . followed by 1 or more digits (\d) at the end of the string ($)), but doesn't capture it as part of the overall match.
The net effect is that only what .+ captured - everything before the lookahead assertion's match - is replaced with 'XX.XX.XX'.
Applied to the above example input string, 10.11.12.50:
(?=\.\d+$) matches the .-prefixed digit group at the end, .50.
.+ matches everything before .50, which is 10.11.12.
Since the (?=...) part isn't captured, it is therefore not included in what is replaced, so it is only substring 10.11.12 that is replaced, namely with XX.XX.XX, yielding XX.XX.XX.50 as a result.
I need to use Perl-compatible regex to match several strings which appear over multiple lines in a file.
The matches need to appear in any order (server servernameA.company.com followed by servernameZ.company.com followed by servernameD.company.com or any order combination of the three). Note: All matches will appear at the beginning of each line.
In my testing with grep -P, I haven't even been able to produce a match on simple string terms that appear in any order over new lines (even when using the /s and /m modifiers). I am pretty sure from reading I need a look-ahead assertion but the samples I used didn't produce a match for me even after analyzing each bit of the regex to make sure it was relevant to my scenario.
Since I need to support this in Production, I would like an answer that is simple and relatively straight-forward to interpret.
Sample Input
irrelevant_directive = 0
# Comment
server servernameA.company.com iburst
additional_directive = yes
server servernameZ.company.com iburst
server servernameD.company.com iburst
# Additional Comment
final_directive = true
Expectation
The regex should match and return the 3 lines beginning with server (that appear in any order) if and only if there is a perfect match for strings'serverA.company.com', 'serverZ.company.com', and 'serverD.company.com' followed by iburst. All 3 strings must be included.
Finally, if the answer (or a very similar form of the answer) can address checking for strings in any order on a single line, that would be very helpful. For example, if I have a single-line string of: preauth param audit=true silent deny=5 severe=false unlock_time=1000 time=20ms and I want to ensure the terms deny=5 and time=20ms appear in any order and if so match.
Thank you in advance for your assistance.
Regarding the main issue [for the secondary question see Casimir et Hippolyte answer] (using x modifier): https://regex101.com/r/mkxcap/5
(?:
(?<a>.*serverA\.company\.com\s+iburst.*)
|(?<z>.*serverZ\.company\.com\s+iburst.*)
|(?<d>.*serverD\.company\.com\s+iburst.*)
|[^\n]*(?:\n|$)
)++
(?(a)(?(z)(?(d)(*ACCEPT))))(*SKIP)(*F)
The matches are now all in the a, z and d capturing groups.
It's not the most efficient (it goes three times over each line with backtracking...), but the main takeaway is to register the matches with capturing groups and then checking for them being defined.
You don't need to use the PCRE features, you can simply write in ERE:
grep -E '.*(\bdeny=5\b.*\btime=20ms\b|\btime=20ms\b.*\bdeny=5\b).*' file
The PCRE approach will be different: (however you can also use the previous pattern)
grep -P '^(?=.*\bdeny=5\b).*\btime=20ms\b.*' file
I have two variables such as:
path='data\voc11\SegmentationClassExt\%s.png'
name='123'
I want to concatenate two strings into one like so:
data\voc11\SegmentationClassExt\123.png
I used the code below:
sprintf(path, name)
However I receive the following error:
Warning: Control Character '\S' is not valid. See 'doc sprintf' for control characters valid in the format string.
ans =
dataoc11
I am using MATLAB on Windows. Could you give me any solution for that. I tried to change path='data\\voc11\\SegmentationClassExt\\%s.png' and when I did that, the above code will work. However, the current data is
path='data\voc11\SegmentationClassExt\%s.png';
use the matlab function fullfile
filename = fullfile ( path, [name '.png'] );
or
filename = fullfile ( path, sprintf ( '%s.png', name ) );
Note: you should avoid using path as a variable as it is already a Matlab function
Before we start, it's highly advised that you do not use path as a local variable. path is a global variable that MATLAB uses to resolve function scope, especially if you are going to use any functions from toolboxes. Overwriting path with your own string will actually make MATLAB not function properly. Use a different variable name.
Now to resolve your problem, you can use either fullfile as what #matlabgui has suggested, or if you don't care about OS compatibility and are only working in Windows, you can either manually change the path as you have placed so that you can introduce two back slashes and it will indeed work on Windows OS, or you can perhaps use a string replace function so that all back slashes will be accompanied with an additional back slash.
Either one of these two methods will work:
Method 1 - Using regular expressions
pat = 'data\voc11\SegmentationClassExt\%s.png';
pat_new = regexprep(pat, '\\', '\\\\');
The function regexprep performs a string replacement by regular expressions. We search for all single backslashes and replace them with double backslashes. Note that the single back slash \ is a special character in regular expressions so if you explicitly what to look for back slashes, you must place an additional back slash beside it.
Method 2 - Using strrep
pat = 'data\voc11\SegmentationClassExt\%s.png';
pat_new = strrep(pat, '\', '\\');
strrep stands for String Replace. It works very similar to regular expressions as we have discussed above. However, what's nice is that you don't have to append an additional back slash when looking for the actual character.
Once you do this, you can use sprintf as normal:
pat_new = sprintf(pat_new, name);
I've got a bunch of directory names and file names, some are absolute path, some are relative path. I just wish to get the 2 leading parts of each path. Input:
D:\a\b\c\d.txt\
c:\a
\my\desk\n.txt
you\their\mine
I expect to get:
D:\a
c:\a
\my\desk
you\their
Is there a convenient way in PowerShell to achieve this?
You can sometimes get your hand slapped for suggesting string manipulation as it can sometimes be "unreliable". However your test data contains 3 different possibilities. Also, never seen someone looking for the first parts from a path.
I present a simple solution the nets your desired output as you have it in your question
"D:\a\b\c\d.txt\","c:\a","\my\desk\n.txt","you\their\mine" | ForEach-Object{
($_ -split "(?<=\S)\\")[0..1] -join "\"
}
I needed to use a lookbehind since your sample output contains a leading a leading slash that you wanted to retain. It splits every string on slashes that have a non white-space character in front of them.
This would not return the correct path for UNC's. Split-Path would be the obvious choice if you only wanted a single portion of the path. I suppose you could nest the call to get 2 but at this time I am unable to find a simple way to account for all of your examples with the same logic.