It seems to me that there are two ways to run Matlab in batch mode:
the first one:
unset DISPLAY
matlab > matlab.out 2>&1 << EOF
plot(1:10)
print file
exit
EOF
The second one uses option "-r MATLAB_command":
matlab -nojvm -nosplash -r MyCommand
Are these two equivalent?
What does "<< EOF" and the last "EOF" mean in the first method?
Thanks and regards!
The first method simply redirects the standard output > matlab.out and the standard error 2>&1 to the file matlab.out.
Then it uses the heredoc way of passing input to MATLAB (this is not specific to MATLAB, it is a method of passing multiple lines as input to command line programs in general).
The syntax is << followed by an unique identifier, then your text, finally the unique id to finish.
You can try this on the shell:
cat << END
some
text
multiple lines
END
The second method of using the -r option starts MATLAB and execute the statement passed immediately. It could be some commands or the name of a script or function found on the path.
It is equivalent to doing something like:
python -c "print 'hello world'"
Refer to this page for a list of the other start options.
Related
In a file S.m I store:
function s = S(a, b)
s = a + b;
I try to call the function from ssh shell like this:
matlab -r -nodisplay "S 3 5" > sum.txt
and I get a "not enough arguments in input" error. Can anyone see the reason for that?
The -r argument introduces the command to execute. The two cannot be separated by other arguments. That is, you can write
matlab -nodisplay -r "S 3 5" > sum.txt
or
matlab -r "S 3 5" -nodisplay > sum.txt
to get MATLAB to run the function S with input arguments '3' and '5'. See the official documentation of the UNIX command matlab for more information. There is a separate documentation page for Windows, where different options are allowed, but the -r switch should still work.
Do note that the MATLAB statement
S 3 5
is equivalent to
S('3','5')
That is, the arguments are seen as strings. Convert them to numbers using the str2double function.
I have a DOS batch-file MYDOS.BAT containing:
My C-application (myApp.exe) reading an input-file (inputFile) from the DOS-command line
myApp.exe analyses inputFile and exits/returns with a code=N
How can I pass value N into my MATLAB script?
E.g: MYDOS.BAT is run by DOS>MYDOS inputFile and contains the following lines:
myApp %1
echo %ERRORLEVEL%
set samplerate=%ERRORLEVEL%
echo %samplerate%
...
C:/... matlab mymatlab.m ...
HOW CAN I THEN PASS the value %samplerate% into my mymatlab.m script?
You can use the system command to use DOS commands in Matlab. Use doc system to see the documentation.
System can have 2 outputs. The first one is a status, which will tell you if the operation succeeded. The second one is the output to the command prompt. You can parse this to get your value. You could use the following code as a guide for your situation:
[status,cmdout]=system('MYDOS.bat');
cmdout will contain the string that you are echoing to the command prompt.
I am basically looking for a way to do this
list=$(command)
while read -r arg
do
...
done <<< "$list"
Using sh intead of bash. The code as it is doesn't run because of the last line:
syntax error: unexpected redirection
Any fixes?
Edit: I need to edit variables and access them outside the loop, so using | is not acceptable (as it creates a sub-shell with independent scope)
Edit 2: This question is NOT similar to Why does my Bash counter reset after while loop as I am not using | (as I just noticed in the last edit). I am asking for another way of achiving it. (The answers to the linked question only explain why the problem happens but do not provide any solutions that work with sh (no bash).
There's no purely syntactic way to do this in POSIX sh. You'll need to use either a temporary file for the output of the command, or a named pipe.
mkfifo output
command > output &
while read -r arg; do
...
done < output
rm output
Any reason you can't do this? Should work .. unless you are assigning any variables inside the loop that you want visible when it's done.
command |
while read -r arg
do
...
done
I want to create scipt to faciliate producing local text file extracts from Hive.
This is to basically execute commands like below:
hive -e "SET hive.cli.print.header=true;SELECT * FROM dropme"|perl -pe 's/(?:\t|^)\KNULL(?=\t|$)//g'>extract/outbound/dropme.txt
While the above works like a charm I find it quite problematic to implement through the parametrized following script (much simplified):
#!/bin/sh
TNAME=dropme
SQL="SELECT * FROM $TNAME"
echo $SQL
echo "SQL: $SQL"
EXTRACMD="hive -e \"SET hive.cli.print.header=true;$SQL\"|perl -pe 'BEGIN{if(defined(\$_=<ARGV>)){s/\b\w+\.//g;print}}s/(?:\t|^)\KNULL(?=\t|$)//g'>extract/outbound/$TNAME.txt"
echo "CMD: $EXTRACMD";
${EXTRACMD}
When run I get: Exception in thread "main" java.lang.NumberFormatException: For input string: "e"
I know there may be many flavours you can print the text or execute command. For instance the line echo $SQL prints me list of files in the directory instead:
SELECT file1.txt file2.txt file3.txt file4.txt FROM dropme
while the next one: echo "SQL: $SQL" gives just what I want: SQL: SELECT * FROM dropme
echo "CMD: $EXTRACMD" prints the (almost) the command to be executed. Almost, as I see \t in perl code being expanded:
CMD: hive -e "SET hive.cli.print.header=true;SELECT * FROM dropme"|perl -pe 'BEGIN{if(defined($_=<ARGV>)){s\w+\.//g;print}}s/(?: |^)\KNULL(?= |$)//g'>extract/outbound/dropme.txt
Maybe that's still ok, but what I want is to be able to copy&paste this command into (other) terminal and execute as the command I put at the top. Ideally I would like that command to be exactly the same (so with \t there)
Biggest problem I have comes when I try to execute it (${EXTRACMD} line). I'm getting the error:
Exception in thread "main" java.lang.NumberFormatException: For input string: "e" …and so on, irrelevant as bash treats every 'word' as single command here. I assume as I don't even know what is really tries to run (prior print attempt obviously doesn't help)
I'm aware that I have multiple options, like:
escaping special characters in the command definition string (like I did with doublequotes)
experimenting with echo and $VAR, '$VAR' or "$VAR"
experimenting with "${EXTRACMD}" or evaluating through eval "${EXTRACMD}"
experimenting with shopt -s extglob or set -f
but as number of combinations is quite large and with my little bash experience I feel it's better to ask for good practice here so my question is:
Is there a way to print a (complex/compound shell) command first and subsequently be able to execute it (exactly as per printed output)? In this case it would be printing the exact command from the top, then executing it the same way as by manually copying that output into terminal prompt and pressing Enter.
Do not construct commands as strings. See http://mywiki.wooledge.org/BashFAQ/050 for details.
That page also talks about a built-in way of getting the shell to tell you what it is running (section 6).
If that doesn't do what you want you can also, with bash, try using printf %q\\n "${arr[*]}".
I need to create output files that include the input I'm providing. For example, a run of the program might look like:
Input command: do_things
Things have been done.
Input command: stop_doing_things
Things are no longer being done.
Where "do_things" and "stop_doing_things" are input from the user.
How can I output all of the above to a file using command prompt functions?
It's not clear what environment using "script " command linux will open a new shell and save everything done it to
This works for you, if you run it at last...
CMD > D:\mycmdout.txt
In that case, maybe you can capture your input as a variable. Echo the variable into the >> mycmdout.txt, then procede with the actual commands, again piped into >> mycmdout.txt as Sunny suggested.
SET /P variable=EnterInputHere
echo %variable% >> mycmdout.txt
EDIT: Be sure to use double >> as to append result to file.