I'm trying to manipulate an image with both read and imfinfo commands. Octave gives a syntax error for this command.
imfinfo(C:Users\konra\Documents\work_stuff\Lochow\210329_Pacitti\210810_photos\DJI_0002.jpg)
^
The little carrot is under the "i" in 210329_Pacitti
You did not set the path between apostrophe like this
imfinfo('C:Users\konra\Documents\work_stuff\Lochow\210329_Pacitti\210810_photos\DJI_0002.jpg')
Related
wkhtmltopdf tool convert html document to pdfs. But I want to specify the left margin. What should the syntax be?
$ wkhtmltopdf --margin-left=10 ex1.html ex1.pdf
Unknown long argument --margin-left=10
Every terminal program may vary in its syntax a bit. Try
wkhtmltopdf --help
To see if there's a commands list.
Also found a manual https://wkhtmltopdf.org/usage/wkhtmltopdf.txt when searched for it. Suggests that the syntax is:
wkhtmltopdf --margin-left 10mm
All I needed was to give 1 space between the option and the value and 2 spaces for the next option
wkhtmltopdf --margin-left 10 --margin-right 10 ex1.html ex1.pdf
I have installed the Ruby environment manager rbenv, Ruby, RubyGems, and PNGlitch (on macOS). Now how do I use PNGlitch?
The best documentation I have been able to find is on this page, and here's an example of the syntax given:
How to use this library: The Simple Way
png = PNGlitch.open '/path/to/your/image.png'
png.glitch do |data|
data.gsub /\d/, 'x'
end
png.save '/path/to/broken/image.png'
png.close
Okay, great. When I insert my file paths, save that code as an .rb file, and open it, I just get:
test.rb: command not found
If I paste it directly into Terminal I get:
png = PNGlitch.open '/Users/username/Documents/testimage.png'
-bash: png: command not found
ComputerName:~ username$ png.glitch do |data|
> data.gsub /\d/, 'x'
-bash: png.glitch: command not found
-bash: data: command not found
-bash: data.gsub: command not found
ComputerName:~ username$ end
-bash: end: command not found
ComputerName:~ username$ png.save '/Users/username/Documents/testimage_glitched.png'
-bash: png.save: command not found
ComputerName:~ username$ png.close
I also tried the syntax given on this page and entered:
pnglitch /Users/username/Documents/testimage.png –filter=Sub /Users/username/Documents/testimage_glitched.png
...this resulted in getting the following message:
tried to create Proc object without a block
Usage:
pnglitch <infile> [--filter=<n>] <outfile>
Options:
-f, --filter=<n> Fix all filter types as passed value before glitching.
A number (0..4) or a type name (none|sub|up|average|paeth).
--version Show version.
-h, --help Show this screen.
↑ I guess this is the developer's idea of documentation. 🤣
Well, trying to follow that example I also did this:
pnglitch </Users/username/Documents/testimage.png> [--filter=<2>] </Users/username/Documents/testimage_glitched.png>
...but that only resulted in:
-bash: syntax error near unexpected token 2
(I chose 2 because apparently that corresponds to the "Sub" filter.)
I tried variants of this syntax as well, including omitting characters <> and [].
There must be some assumed knowledge here that I don't have. So what I would like to know is:
How can I actually use PNGlitch to glitch a PNG image?
How can I use PNGlitch to glitch all the PNG images in a folder?
Any additional advice on using different filters would also be appreciated.
Thank you.
There's a lot going on here that needs to be cleared up.
Ruby scripts need Ruby to run
You can't just paste these into bash and expect anything useful to happen.
The usual procedure is one of two variants. Either:
Create a .rb script, like example.rb
Run ruby example.rb where that's your script name at the end.
Or use the "hash-bang" method:
Create a script with #!/usr/bin/env ruby as the very first line.
Make this script executable with chmod +x example.rb
Run this script directly, ./example.rb or whatever path it has.
Note that example.rb by itself will not work unless it is in your path, hence the ./ is necessary.
Command line example syntax
Here <name> has special meaning, where it's just a way of saying name as if it had italics or special formatting. On a text-mode terminal it's not practical to add syntax like that, it's limited to ASCII in most cases, so this tradition evolved.
Within the POSIX shell > and < have special meaning, they're used to, respectively, redirect input to or from a file. For example, ls > ls.txt dumps the output of ls into a file called ls.txt, while cat < ls.txt reads in the contents of ls.txt and displays it.
Things like [name] mean optional arguments, like [--help] means the --help argument is optional.
Within the POSIX shell [ and ] have special meaning. They can be used in an if construct, but more commonly in file wildcards, like l[abc].txt means any of la.txt, lb.txt or lc.txt.
Putting this together it's possible to understand the notation used here:
pnglitch <infile> [--filter=<n>] <outfile>
Where that means infile is your "input file" argument, and outfile is your "output file" argument, and --filter is an optional argument taking n as an input.
So you call it like this:
pnglitch input.png output.png
Or with an option, like you did:
pnglitch testimage.png --filter=sub testimage_glitched.png
Though note I've used lower-case sub as that's precisely what's in the help output and following casing conventions usually matters.
This is killing me. I have a config file, "myconfig.cfg", with the following content:
SOME_VAR=2
echo "I LOVE THIS"
Then I have a script that I'm trying to run, that sources the config file in order to use the settings in there as variables. I can print them out fine, but when I try to put one into a numeric variable for use in something like a "seq " command, I get this weird "invalid arithmetic operator" error.
Here's the script:
#!/bin/bash
source ./myconfig.cfg
echo "SOME_VAR=${SOME_VAR}"
let someVarNum=${SOME_VAR}
echo "someVarNum=${someVarNum}"
And here's the output:
I LOVE THIS
SOME_VAR=2
")syntax error: invalid arithmetic operator (error token is "
someVarNum=
I've tried countless things that theoretically shouldn't make a difference, and, surprise, they don't. I simply can't figure it out. If I simply take the line "SOME_VAR=2" and put it directly into the script, everything's fine. I'm guessing I'll have to read in the config file line by line, split the strings by "=", and find+create the variables I want to use manually.
The error is precisely as indicated in a comment by #TomFenech. The first line (and possibly all the lines) in myconfig.cfg is terminated with a Windows CR-LF line ending. Bash considers CR to be an ordinary character (not whitespace), so it will set SOME_VAR to the two character string 2CR. (CR is the character with hex code 0x0D. You could see that if you display the file with a hex-dumper: hd myconfig.cfg.)
The let command performs arithmetic on numbers. It also considers the CR to be an ordinary character, but it is neither a digit nor an operator so it complains. Unfortunately, it does not make any attempt to sanitize the display of the character in the error message, so the carriage return is displayed between the two " symbols. Consequently, the end of the error message overwrites the beginning.
Don't create Unix files with a Windows text editor. Or use a utility like dos2unix to fix them once you copy them to the Unix machine.
I have problems with command 'load'.
For example my script is something like this:
set xlabel ‘blabla’
But when i try to load this, I get:
load '/Users/.../gnuplot.txt'
^
"/Users/.../gnuplot.txt", line 1: invalid character ?
I figured out that adding "reset" before the whole script change the error message:
set xlabel ‘blabla’
^
"/Users/.../gnuplot.txt", line 2: invalid character ?
But when I write everithing into the terminal by myself, I get no errors...
Any idea how to fix it??
Thanks
You are using the wrong quotation marks (Left and Right single quotation marks, codepoints U+2018 and U+2019).
You must use ASCII single or double quotation marks, either ' (0x27) or " (0x22).
Try putting this line before your load command
set encoding utf8
The invalid character smacks of using the wrong character set.
I'm trying to create a mask and use the bitwise operator "&" to compare to another variable and see the output. Let there be code:
mask=00000
mesk=00010
mosk=$mask&$mesk
echo $mosk
echo meec
I'm trying to expand this functionality to be able to have more characters (different error/success codes), but those lines just don't work: Executing the script will print an empty line, then "meec".
I came from an object oriented programming background, and although I've read through several documents on this subject, it seems there's something I'm missing.
Any help would be appreciated.
Edit: For some reason, turns out the code doesn't work, it says "command 00010 not found" >_>
It's because usually the & character in the shell is the modifier to put a command in the background.
You have to use Arithmetic Expansion of Bash (for example) for it to work:
mosk=$(($mask & $mesk))