Programming :: BASH Conditionals - Passing Condition As Variable ?
Sep 17, 2009
I'm trying to implement an assert function similar to:[url]
However, I'm having trouble with file existence testing when the file name has a space in it.
I have distilled the problem down to the following:
This code works as expected, printing 'yes' if '~/test file' exists, and no if not.
Code:
However, this code gives an error.
Code:
The error:
Code:
Which tells me that it is splitting ["~/test file"] into ["~/test] and [file"]. Why? Is there a way around this?
Note that if you simply use a file path without a space, both cases work perfectly. Is this a BASH bug possibly? I just can't understand why the first would work, but the second wouldn't.
I have a file with around 1000 IP addresses in it and I need to be able to ssh into each one of them, run a single command, and then exit. I already know the ssh command I want to run and it looks like this:
(I know shpass is not good to use and keys are the correct way but I don't have any other options in this scenario.) if these ip addresses were in a .csv file, by themselves with no other information, how would I create a script to do the above command to each ip until the end of the file?
An input filename ($1) is fed into mediainfo, which by the use of grep and cut spits out a single number which is the aspect ratio. This is then divided by bc into 320, which gives the desired height dimension for the file that I want ffmpeg to create for me. Finally, ffmpeg runs using the calculated dimensions... Basically, it's the passing of the $ASPECT variable to bc that seems to fail. It looks like bc won't read the output from the mediainfo line... It always crashes out with:
Code:
(standard_in) 1: illegal character: ^M I've tried doing something even simpler like this to debug by just trying it to display the calculation on the screen:
need to modify some scripts to repeat the commands in them until a variable returns a proper value. I need it to add some redundancy to some scripts i use to upload files to a remote server.This is an example of a portion of those scripts:
I want to build on the code from /etc/apt/apt.conf.d/05etckeeper to work with Snapper, the new-in btrfs (et al) snapshot package.
Code: Select allDPkg::Pre-Invoke    { "if [ -x /usr/bin/etckeeper ]; then etckeeper pre-install; fi"; }; DPkg::Post-Invoke   { "if [ -x /usr/bin/etckeeper ]; then etckeeper post-install; fi"; };
The etckeeper code will work well as a template, but I need to pass a parameter between the pre- and post- instances. The parameter is obtained from the pre- invocation and passed to the post- invocation.I know that something similar to my quest is done with the 'pid' but how to do it in the 'standard' way. Happily there can't be multiple dpkg instances running concurrently (prevented by dpkg?) so I don't have to worry about that issue.
Q1. What is the 'standard' way of passing parameters about?
Code: Select allsnapper -c etc create -t pre -p   (which 'prints' the parameter (int) to pass to the following invocation) snapper -c etc create -t post --pre-number <parameter> in place of the two etckeeper calls.
Q2. How do I pick up the 'printed' output of the 'pre' call? I think it's just a 'get' from the stream but perhaps I've missed something.?
I want to know is there some more efficient way of passing a pointer to a local variable as a parameter to a function in x86 asm? Right now I have to move the base pointer to a temp register, subtract from the register and pass that, like this (assuming a local var at esp-4):
Code: mov eax, ebp sub eax, 4 push eax Is there a better way?
I'm having some trouble this morning to send a SQL query to our Oracle DB server in PHP. When I try to pass my value "OF/110246801A01" as variable it tell's me "Warning: oci_bind_by_name(): ORA-01036: illegal variable name/number"
Say, i have an imaginary std library function, which I want to call.
Code: void std_lib_func(ObjectType *param);
Now in my c++ program, I have a main() function, and I will like to call a customized function (which will in turn call the std lib function) from the main function, as below:
Code: int main() { ObjectType *aobj; customized_func(aobj); } [Code]...
I tried the below but get an error that the std lib function is expecting a ObjectType* param, not aobj. How should I work this out.
I'm trying to read content of file to variable and use this variable in for loop. The problem is, when I have c++ comment style in file - /*. Spaces in line are also interpreted as separated lines.
For example:
Code:
Changing $files to "$files" eliminate these problems but causes that whole content of variable is treated as one string (one execution of loop).
I have a bash script called bash I am trying to execute from PHP. I think I have that right (not sure yet). Ideally let me explain what I am doing. The front end will pass a variable from a text entry box, called New_Task, the New_Task needs to be executed in the bash script and the output needs to be displayed back on the front end. So let me give some code and let me know what you all think.bash code is quite long, but essentially it is made to take a entry and create a task out of it. eg. "svn branch <Task Name>". The code below is getting the New_Task variable passed from the text entry box ($NewTask) and I have an exec for the bash script, but I am not sure it is working, I need to add some code to see the input in the front end.PHP back end code:PHP Code:
function mTaskCreator() { $strAction = $this->_objUserContext->mGetPostVar( 'acti
I get no print to stdout on screen from the C code.Does bash somehow block or mask it?I get print from bash. I get this error in the non-test bash script like: let "rdval = $rdstr"syntax error: operand expected (error token is " ")The let command prints rdval= but I presume this is due to the printf test statements getting in the way.I am getting no compile errors. Why does the C code not print the values specified?
I am not sure if that Subject really explains it, basically I have a script that executes a CLI java-applet that requires a passphrase from the user. I can easily execute this by issuing the -p argument followed by the passphrase however that shows up on possible logs or at least on the results of the ' ps ' command. If you do not supply this -p argument it provides a new line with the echo " Enter Passphrase: " and asks for input.
how can I provide a result/input for the Passphrase request and is it still possible to throw this application in the background with the ' & ' following the command? I have seen a few examples that show a /bin/expect that expects a result and sends a command however I would like to refrain from any extra dependencies. Example of Regular Execution of application:
Now in my bash script, I want to get the output /home/user instead of $HOME once read. So far, I have managed to get the $HOME variable but I can't get it to echo the variable. All I get is the output $HOME.
"While ; do ; done" is very convenient for SH coding. However sometimes you may be annoyed by your computed variable within the "while do done" type loop. What to do how to pass it out of the loop to the outside of the bash code? A solution is to write it into the /tmp or on the disk... and to call it back after. - not elegant... really not... Anyone would know a trick another alternative that would look nicer?
Code: # Count file total size TOTAL_SIZE=0 LISTOFFILES=`cat "$HOME/.fvwmoscfg/fvwmburnerlist.lst"` echo "$LISTOFFILES" | while read i ; do SIZE=`du -bs $i | cut -f 1` TOTAL_SIZE=`expr $SIZE + $TOTAL_SIZE` echo "$TOTAL_SIZE" > "$HOME/.fvwmoscfg/fvwmburnerlisttotalsize.lst" done TOTAL_SIZE=`cat $HOME/.fvwmoscfg/fvwmburnerlisttotalsize.lst`
echo "The total size of all files and folders is : $TOTAL_SIZE"
Just a simple BASH for loop to read the file path from a text file (clean.txt) echo the variable for debug purposes, and scp it to a server I have using port 50 for SSH.
I've already formatted the entries in clean.txt to handle spaces correctly, using sed replacement.
Example from the clean.txt file:
Code: /MP3/NAS000000001/Barenaked Ladies/Barenaked Ladies - Barenaked For The Holidays/20 Auld Lang Syne.mp3 /MP3/NAS000000001/Barenaked Ladies/Barenaked Ladies - Barenaked For The Holidays/14 Deck the Stills.mp3
I want to write a c program with some shell scripts.Now For a simple C program. I am Setting a variable called val2 in bash, now I want to use bash variable val2 in C code. How do I do that?The above doesn't work (coz its spawning a different memory space and when shell script ends the variable dies with it as per my research but how do I keep them in same memory space)Also Is there any Good reference where they teach how to integrate C and Bash Together?
i've just started to learn about functions in Bash scripting. I'm able to set the functions and execute the commands correctly. However, if my_var is set in the first function and then later in the script in the script the 2nd function is called, it doesn't seem to remember my_var and quits (at least i suspect this is the problem).
Here's my code (it requires yad available via webupd8. org). My specific problem seems to lay in line #27 where if we view the changelog and then exit that window, it returns to the "main" function but any subsequent commands cause a crash. Is this because of the get command on line #29? It's presumably now out of scope after calling menu on line #25?
I have a program that loops over each word in a sentence. I need to append a constant to the beginning and end of each word. It works up until the last word on the line.
I was wondering if possible in bash for a variable to take the value of a function, I mean the function returns a value and a variable will take it. example:
The output of following code is not like it's intended ...
Code:
This is the output:
Code:
Test prepending ...apple is a nice word, hour is a nice word, But of course what I want to do in the first set of commands is to prepend the word "an" to the words "apple" and "hour" in the for-loop.
Within a bash script, I'm attempting to redirect file descriptors with exec, e.g. exec 3>&1 1>&2; however, I'd like to do something like exec $FD>&1 1>&2, which doesn't work because bash tries to execute the value of $FD. Various placements of eval fail, as well. Is there a way around this, or am I stuck hard-coding the descriptor?
