This is related to u-boot.
I looked at this link (How to test the return of a command in U-Boot CLI) but it doesn't cover what I need. I also checked some other pages related to the 'test' command in u-boot but I can't figure out how to do what I would like. So there it is.
I have a u-boot command on a SBC which returns a set of information as text printed on the screen, where some part are strings representing versions. What I would like is to check whether the command return contains some specific strings to choose automatically what to do.
I have seen a few 'test' command help, but I couldn't figure out how to do this type of check on the text returned by this command. My goal is to have a set of nested ifs to choose in the different cases, or anything equivalent. If regex can be used, they perhaps could be helpful.
Does anybody know how to do this?
Thank you.
In U-Boot's hush shell there is no support for pipes. There is also no command like grep. So there are no means to succeed via U-Boot's built-in shell commands.
If you have access to the source of the command that you are executing, you could change it and use function env_set() to write the relevant data to environment variables and then use test for your purposes.
Related
I know how to get the stdout into a file using dup/dup2 system calls, but how do I get the entire output that would be normally shown on my terminal(including the prompt that says my username along with the $ symbol and the current working directory) to a file?
Yes you can, but this may be difficult in many details (depending on your expert level). For the shell to behave normally (I would mean exactly as in a terminal), then it needs to interact with a terminal (special system object). So you need to create a program that behave like a terminal, this what pseudo-terminals devices (/dev) are intended for. Read documentation about this to implement it but roughly, your application should behave like the user so should be connected to the slave side of the pseudo-terminal, and the shell to the master side of the pseudo-terminal. Then you can easily log real inputs made by the user and catch outputs made by the shell.
Can't comment cause of low reputation.
I would say there is no way to do that inside a code in C. Instead, you could use bash for example to redirect everything to a file, and leave the code in C as it is.
In this way you have all the info you want to save: prompt, current directory, call to the program (including flags), and of course the output of the program.
Well, you can do:
-For bash prompt PS1: Echo expanded PS1 (in case you want it expanded, if not there is a simple way to do it just echong PS1)
- For executed command: https://unix.stackexchange.com/questions/169259/how-to-capture-command-line-input-into-logfile-and-execute-it-at-the-same-time
- Standard output and error output: Redirect stderr and stdout in a Bash script
And that's all you want to capture, I think.
Look up the script command in Unix systems. If you want to capture all keyboard and std in/out for a command, use the script executable. If you want to see how it's done, look up the source.
I am writing scripts in tcl for a project I am working on.
I wanted to automate things as much as possible and wanted to not touch the source code of the script as far as possible. I want to run the main script file from a .bat or .job file sort of thing where I pass the command to execute the script along with the arguments.
I have referred to this post on stackoverflow:
How to run tcl script in other tcl script?
And have done pretty much the same thing. However, since my script is naked code rather than a single huge proc, I dont have the "args" parameter to read the arguments I wanted to pass.
For example, if script1.tcl is the main file containing the naked code, I want a file script2.job or script2.bat such that,
<command-to-run-script1.tcl> <mandatory-args> <optional-args>
is the content of the file.
Any suggestions on how I can implement the same?
To run a Tcl script, passing in some arguments, do:
tclsh script1.tcl theFirstArgument theSecondArgument ...
That's how it works in CMD scripts/BAT files on Windows, and in shell scripts on all Unixes. You might want to put quotes around some of the arguments too, but that's just absolute normal running of a program with arguments. (The tclsh might need to be tclsh8.5 or tclsh85 or … well, it depends on how it's installed. And script1.tcl might need to be a full path to the script.)
Inside the script, the arguments (starting at theFirstArgument) will appear in the Tcl list in the global argv variable. Note that this is not args, which is a feature of procedures. There are lots of ways of parsing the list of arguments, but any quoting supplied during the call itself should have been already stripped.
Here's a very simple version:
foreach argument $argv {
puts "Oh, I seem to have a >>$argument<<"
}
You probably need something more elaborate! There's many possibilities though, so be sure to be exact to get more focussed ideas.
If you're calling Tcl from another Tcl script, you need to use exec to do it. On the other hand, you can make things a bit easier for yourself in other ways:
exec [info nameofexecutable] script1.tcl theFirstArgument theSecondArgument ...
The info nameofexecutable command returns the name of the Tcl interpreter program (often tclsh8.5 or wish86 or …)
I'm trying to write a makefile to replace one of the scripts used in building a fairly large application.
The current script compiles one file at a time, and the primary reason for using make is to parallelise the build process. Using make -j 16 I currently get a factor of 4 speedup on our office server.
But what I've lost is some readability of the output. The compilation program for a file bundles up a few bits and pieces of work, including running custom pre-compilers, and running the gcc command. Each of these steps outputs some information, and I would prefer it to buffer the output from the command, and then show the whole lot in one go.
Is it possible to make make do this?
If you upgrade to GNU make 4.0, then you can use the built-in output synchronization feature to get what you want.
If you don't want to upgrade, then you'll have to modify each of your recipes to be wrapped with a small program that manages the output. Or you can set the SHELL variable to something that does it for you. Searching the internet should give you some examples.
A simple way to accomplish this is to send all the log output a to log directory with each file named, say:
log_file_20131104_12013478_b.txt // log_file_<date>_<time>_<sequence letter>.txt
and then simply cat them all together as your last make job in the dependency chain:
cat log_dir/log_file_20131104_12013478_*.txt > log_file_20131104_12013478.txt
With makepp this is the default behaviour as soon as you use -j. All the individual outputs (and entering dir messages) get collected and are output together as soon as the command terminates.
I am wanting to make a terminal app that stores information about files/directories. I want a way to keep the information if the file is moved or renamed.
What I thought I could do is have a function execute before any command is run. I found this:
http://www.twistedmatrix.com/users/glyph/preexec.bash.txt
But I was wondering if this would be a good way to go about it. Or should I do something else?
I would like to call that function from a C program whenever mv is entered I suppose.
If what you're trying to do is attach some sort of metadata to files, there's a much better supported way to do that -- extended attributes.
Another solution might be to use the file's inode number as an index into a database you maintain yourself.
Can you alias the mv command? in .profile or .bashrc
alias mv=/usr/bin/local/mymv
where mymv is a compiled executable that runs your C code function and calls /usr/bin/mv.
precmd and preeexec add some overhead to every bash script that gets run, even if the script never calls mv. The downside to alias is that it requires new code in /usr/local and if scripts or users employ /usr/bin/mv instead of mv it will not do what you want. Generally doing something like this often means there is a better way to handle the problem with some kind of service (daemon) or driver. Plus, what happens if your C code cannot correctly handle interesting input like
mv somefille /dev/null
If you want to run command each time after some command was executed in the terminal, just put the following in ~/.bashrc:
PROMPT_COMMAND="your_command;$PROMPT_COMMAND"
If you want your command to be executed each time before mv is executing, put the following in ~/.bashrc:
alias mv="your_script"
Make sure that your script will execute real mv if needed.
You can use inotify library to track filesystem changes. It's good solution, but once user remove file, it's already gone.
You might be able to make use of the DEBUG trap in Bash.
From man bash:
If a sigspec is DEBUG, the command arg is executed before every
simple command, for command, case command, select command, every
arithmetic for command, and before the first command executes in
a shell function
I found this article when I was forced to work in tcsh and wanted to ensure a specific environemtn variable was present when the user ran a program from a certain folder (without setting that variable globally)
tcsh can do this.
tcsh has special alias, one of which is precmd
This can be used to run a script just before the shell prompt is printed.
e.g. I used set precmd 'bash $HOME/.local/bin/on_cd.sh'
This might be one of the very few useful features in csh.
It is a shame but I don't think the same or similar feature is in bash or other sh derivites (ash, dash etc). Related answer.
Basically I want to do a program almost like a keylogger. The thing is that I as network admin sometimes I don't remember what I did to a machine on certain case, or same times I make howto's and tutorials for linux. I want to record what have i done.
So basically the idea of this program is:
you type the name of the program, (I call it rat for the moment)
$ rat
Welcome everything from now on will be recorded
recording $ ls
file1 file2 file3
recording $ quit
Bye bye
Everything you do will go out to an xml file. Something like this
<?xml version='1.0' encoding='UTF-8' ?>
<rat>
<command>
<input>ls</input>
<output>file1 file2 file3</output>
<err><err>
</command>
</rat>
i am doing some tests with fp_in = popen( input, "w");
and system, but first with popen i cant change directories and with "system i cant properly manage the input and output.
I was also checking if there is something I can do to bash like a plugin but haven't find any information.
At some points if feels like it I should create another shell (which is way beyond my current abilities) or fork bash sh. But it should been that complicated right.
I am open to suggestion where to start.
I am rusty with C, so I am reading again a lot of basic stuff.
With the xml file, later i was thinking on making a program to store this data and/or editing this data so i can create tutials and howto.
I can think of many ways of expanding this up to using printscreen so all the stored images go to a file you can upload to a server (for the moment i am glad to store the data). It could be a usefull tool.
ps. I do know this can be use for evil things too.
There already exists the script command, which will record all input and output into the terminal, writing it into a transcript. I would recommend just using that, unless you have particular needs that it doesn't meet. Actually, the nicest version of script that I've seen has been the NetBSD version, so you may want to look into that if the Linux version doesn't meet your needs.
If you would like to write it yourself, instead of using system, I would recommend that you use fork/exec to create a single shell process, which you copy all input and output into. To get an idea of how this works, I'd recommend looking at the source code for an existing version of script.
Most shells have a script built-in which will simply record the text in- and out- from the command line. Not quite what you're looking for... To my surprise script is not a built in, which means it is a model for building what you want.
The script command does almost what you want: it simply records the text in- and out- from the command line.
If you make your prompt distinctive (so that you can reliably tell the difference between shell commands and everything else) you can post-process the output of script to achieve your goals. Alternately you can hack script to get it to emit the XML you're looking for.
You can also try approaching this from a different angle. Instead of using a regular shell, connect to the machine using ssh or telnet and run your commands that way. Many ssh/telnet clients (PuTTY, for instance) have an option to log all console input and output during the session. You should be able to post-process this log to generate whatever type of logfile that you need.
Depending on your setup, you might not even have to use a second machine (you should be able to ssh into yourself).