I am writing a script that calls a program which writes a lot of lines to stdout continuosly. If the last line in stdout has some regex, THEN, certain variables are updated. My problem is that I don't know how to do that.
A simplified example would be (it's not my exact case, but it I write it here to clarify): suppose I issue a ping command (which writes output to stdout continuously). Every time that the response time is t=0.025 ms, THEN, VARIABLE1=(column1 of that line) and VARIABLE2=(column2 of that line).
I think the following code would work in awk (however, I want the variables in bash and I don't know how to export them)
In the previous code, awk analyzes each line of the output of the ping command as soon as it is created, so the variables $var1, $var2, ... are updated at the appropriate time. But I need the "real-time" updated values of $var1, $var2 in bash, for later use in the script.
At my wit's end I can't find anything that I understand well enough to use. This is for a Unix class, we are working with shell scripting. File1 has 5 in it and File2 has 100 in it.The teacher wants us to read the values then do the math. This is what I have so far:#!/bin/bashvar1='cat File1'var2='cat File2'var3=`echo "scale=4; $var1 / $var2" | bc`echo The final result is: $var3
my script has a variable which comes in the form +00.00 +0.00 -00.00 or -0.00 (the numbers can be any in that form) for any that have a + symbol I need to remove the +, but if it has a - symbol it needs to stay.
i need to make a new variable with the string from the old variable btut without any plus sign. I have tried a lot of different ways with no success, each thing I tried either left the + or removed the entire string. I think this should work but doesn't
Using things like awk/sed, but have managed to cobble together what I needed so far without a problem. The only thing I'm struggling with is to assign the content of a particular line as a variable, and then to use it again throughout the file.
For example, if what I want is the first line of the file to become the variable "from1", and then to replace the word "Subject" in the file with the string "Message from [from1]". What I thought would work
I tried a few diff combinations but nothing seems to work. All I get is the terminal hanging indefinitely.
I have some messy code that I wrote a while back and I am trying to organize it. The program opens xpaint and uses xwit and xte to draw packman and so on. I want to split it all up I am going to add more to it. Basically like i would want drawing packman in one function i guess you could call it and then coloring him or the background in another
What I am trying to accomplish is a way to read only the lines that have been added to the file mylog0 since the last time the script looped (5 seconds). I am open to new suggestions too, I have been stuck on this little script for a few hours already.
I need to check whether a shell script variable contains non-zero numeric data to proceed. The variable should contain numeric values, but may in fact contain zeroes, blank space or nothing. So far, I have tried various combinations of:
Code: if test $variable then if test $variable -gt 0 then echo "good data exists" else "no good data exists" fi fi It partially works, but I get either "too many arguments" or "integer expression expected".
I am supposed to create an environment variable with the PRINTER variable, which should resolve to the word sales. Would the command be like this?: env PRINTER - NAME=SALES (is this the command to create that variable with resolving the word sales to it?)
I am using Red Hat Linux Enterprise 5. I know the theory that -- using export to set environment variable, the environment variable will apply to current and child environment, but without using export to set environment variable, the environment variable will only apply to the current environment. What is the exact definition of "child environment" and "current environment"? For example,
Code: $ var1=123 $ echo "Hello [$var1]" The value of var1 (which is 123) is printed in shell, but I think echo is a command invoked by current shell, and it (the echo command) should be a child environment of current shell and the value of var1 should not (because not using export var1=123) impact echo.