I want 3 UNIX command which use neither standard input nor standard output .
I am still confused that a command with any redirection of using pipes is can be said as a example of not using standard input or standard output
"standard input" is normally what comes from the user's keyboard, or in the case of a pipeline, what comes from the preceding process.
"standard output" is normally what gets sent to the screen, or in the case of a pipeline, what gets sent onto the following process.
So, you seem to be looking for commands that read no input, and produce no output. Here are some that spring to mind:
cd
touch
mkdir
nice
shutdown
true
false
Related
For an example, I have created some feature for automation testing using Behave login_account.feature and choose_product.feature. To run on a single feature, I use this command on the terminal behave -f behave_html_formatter:HTMLFormatter -i login_account.feature.
I want to run on multiple feature login_account.feature and choose_product.feature in one command on the terminal. Anyone, can you give me the example command to run multiple feature using Behave in one command on the terminal?
Thank you in advance.
I think there might be two issues:
I'm not sure if that's the way to run with that formatter. See behave-html-formatter docs for config and example. I can't trial myself as I don't want/need this formatter installed. I would suggest you worry about this after you understand how to run multiple features, which is where issue #2 comes in.
-i expects a single argument, which is a regular expression pattern.
Assuming you are in your features folder, just list the two features with space separator after the behave command:
behave login_account.feature choose_product.feature
Better still, you could use tags. This makes way more sense if you want to run more than the two files in your example. Add a tag at the top of each of the feature files you want to execute e.g. #runme.
Then execute only the ones having the preferred tag:
behave -t #runme
i'm using zsh on my mac (oh-my-zsh) and i don't understand why at the end of my output there is always this character: "%"
If i don't put export TERM="xterm-256color" in my ~/.zshrc i haven't that character:
Usually a bold % (or # for root) with reversed colors is used to signify a "partial" line in the output. That is a line, which is not terminated with a newline character.
As it seems to depend on the value of TERM I suspect an incompatibility between that value and the settings of terminal emulator. Contrary to the warning shown in your second screenshot, you actually should not set TERM in your ~/.zshrc (or anywhere inside the shell session). TERM should always be set by the terminal emulator itself. Its value (in conjunction with the terminfo terminal capability data base) tells the shell and other programs, which features a terminal emulator supports and how to use them. If the value is changed in the shell, the terminal emulator will not know about it. This may lead to programs sending control codes the terminal emulator does not understand correctly or at all.
In order to change the value of TERM you should change it in the terminal emulator settings. According to the iTerm 2 FAQ the settings is to be found at Preferences->Profiles->Terminal->Report Terminal Type.
I personally placed export PROMPT_EOL_MARK='' inside my ~/.zprofile and hide the character.
Writing my first script with after effects to automate some of my process. I want the script to run at startup of AE with some arguments passed via command line so I use the -s command.
Everything is done except for one problem, when I run AfterFX.exe with the -s, for example if i do this:
"PATH_TO_ADOBE_CS6\Support Files\AfterFX.exe" -s "alert('foo')"
It opens after effects and i do get that 'foo' dialog but for some reason After Effects is 'disabled'. What I mean is I can't do anything, not open any project, nothing. all options are grayed out.
Note that if after effects is already running, and I run the command, it doesnt 'disable' after effects and I get the desired result.
I am using windows and after effects CS6.
note: obviously I intend to do something more complex than alert('foo') which was used a minimalist example to show my issue.
figure it out. for those who find this later, the solution is to add app.exitAfterLaunchAndEval = false.. i.e,
"PATH_TO_ADOBE_CS6\Support Files\AfterFX.exe" -s "app.exitAfterLaunchAndEval = false; alert('foo')"
Here is a basic script with getopt command and assigned variables.
If someone were to type in
MyScript -a
with no words or numbers added after the -a, then an error message would pop up! The same happens if you replace -a with any other assigned variables. If I wanted no error message to appear, how would I go about doing this?
Hints/advice is preferred over a simply strict answer!
From the bash manual:
getopts can report errors in two ways. If the first character of optstring is a colon, silent error reporting is used. In normal operation diagnostic messages are printed when invalid options or missing option arguments are encountered. If the variable OPTERR is set to 0, no error messages will be displayed, even if the first character of optstring is not a colon.
Since you tag the question with Unix and don't mention bash, you may or may not be so lucky, but the answer is to read the manual page carefully.
I see console apps print colors and seen apps such as ffmpeg print text over itself instead of a new line. How do I print over an existing line? I want to display fps in my console app either at the very top or very bottom and have regular printfs go there and scroll normally.
I need this for windows, but this is meant to be cross platform, so I will eventually have a linux and mac implementation.
There is two simple possibilities which work on linux as well as windows, but only for one line:
printf("\b"); will return for one character, so you might count how many character you want to backspace and fire this in a loop, or you know that you only write n numbers and do it likeprintf("\b\b\b\b\b\b\b\b\b\b");
printf("text to be overwritten by next printf\r"); this will return the cursor to the beginning of the line, so any next printf will overwrite it. Make sure to write a string of same length or longer so you overwrite it entirely.
If you want to rewrite several lines, there is nothing so portable as ncurses, there is libs for it on practically every operating system, and you don't have to take care of the ANSI-differences.
edit: added link to ncurses wikipedia page, gives great overview and introduction, as well as link list and maybe a translation to your preferred language
Check out ncurses. It has bindings for most scripting languages.
You can use '\r' instead of '\n'.
The ASCII character number 8 (A.K.A. Ctrl-H, BS or Backspace) lets you back up one character. ASCII Character number 13 (A.K.A Ctrl-M, CR or Carriage Return) returns the cursor at the beggining of the line.
If you are working in C try putchar(8); and putchar(13);
The magic of the colors, cursor locating and bliking and so on are inside ANSI escape codes. Any text console capable of handling ANSI codes can use them just printing them out to console (i.e. by means of echo in a bash script or printf() function in C).
Unix terminals support ANSI escape sequences and Windows world used to support them back in old MS-DOS days, but the multibyte console support put an end to this. There is more information here. However there are other ways out of just ANSI sequences printing available on Windows. Moreover if you have Cygwin installed on your Windows maching ANSI codes work just as great as on any Unix terminal.
Many people mention Ncurses library that is the de-facto standard for any gui-like text based applications. What this library does is to hide all the terminal differences (Windows/Unix flavours) to represent the same information as identical as possible across all the platforms, though from my own experience I tell you this is not always true (i.e. typical text window frames change because the especial chars are not available under all character encodings). The counterpart of using ncurses is that it is a complete API and it is much harder to start out with it than simply writing out some ANSI escape sequences for simple things such as change the font color, cleaning screen or moving back the cursor to a random position.
For the sake of completeness I paste an example of use of ANSI sequence under Linux that changes the prompt to blue and shows the date:
PS1="\[\033[34m\][\$(date +%H%M)][\u#\h:\w]$ "
You can use Ncurses -
ncurses package is a subroutine library for terminal-independent screen-painting and input-event handling which presents a high level screen model to the programmer, hiding differences between terminal types and doing automatic optimization of output to change one screenfull of text into another
Depending on the platform which you are developing on there's probably a more powerful API which you could use, rather than old ASCII control codes.
e.g. If you are working on Win32 you can actually manipulate the console screen buffer directly.
A good place to start might be here
http://msdn.microsoft.com/en-us/library/ms683171(VS.85).aspx
I have been looking for similar functions/API which would allow me to access the console as something other than a stream of text for other platforms. Haven't found anything yet, but then again, I haven't been looking that hard.
Hope it helps.