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.
I am trying to read certain lines within a file and give the output of the certain lines that dont equal my value, I think showing you would be easier. There is multiples of these inside one file...
LV Name /dev/vg00/lvol1 LV Status available/syncd LV Size (Mbytes) 300lable/syncd
I want to read everything in the file, if the status is not available then it should display the name (directly above status). If they are all availbale then do nothing. I think I know how to do it which includes putting the info in string form and placing in hash but it is proving to be out of my skill range.
When I put a "test" target in my Makefile containing Code: @echo "CXX= $(CXX)" it tells me "CXX= g++". But I have nothing in the Makefile assigning any value to CXX, and as far as I can tell I have no CXX environment variable (no "CXX" appears when I run the shell command "env", and "echo $CXX" returns a blank line. So where's the g++ value coming from. Is this just built into Gnu Make, or is there a configuration file for make somewhere?
Order of these lines are random... So I cannot delete line #19, for example... And you can see that top four lines I want to delete are pairs. So there might be some clever way to detect the lines, if a line has both "1.9" and "1.11", then delete the line... I am new to perl language. The following is the code I have now... I think I just need to write some code inside the while loop checking if I want to delete the line $dotline before I write to a NEW file.
What is the best way to merge lines, in sed, awk or perl, that occur between certain strings? I'm new to sed scripting and I have been working on this for some time now. I have a large file (sample below) that I need to edit.
What I need looks something like this.
I'm working with a very large file so simply merging all the lines then adding a new line character before ">contig" and after "translated" won't work, at least not with sed.
I'm trying to split a text file into various parts. Everything in between "123" and "break" (including linebreaks) goes into the splitted file.
e.g. using this text file:
This should split into 4 files. However I'm only getting 2 files: one for the line "123break" and one for "123 blah break". The two occurrences that contain linebreaks are being ignored. The .* part of my match should capture linebreaks seeing that I'm using the /s modifier shouldn't it? Even when I use the match /(123 break)/gs it still doesn't capture the first occurrence. I'm using Perl v5.12.3 (from ActiveState) on Windows XP. The text file is also in Windows format.
Code listed below.
The above code generates two files Output_1.txt and Output_2.txt which contain "123break" and "123 blah break" respectively. I want it to generate four files.
I am new to perl and am having trouble adding some strings together.
My full code is below:
The problem is $NewCommandB is always split into two lines, where the second line contains the "/atlas2/<blah>/<etc>/..." string. Since I am generating a .sh file to execute a lot of similar commands I need the string to all be on one line. Any idea why I get this behaviour and any suggestion on how to tell perl to make $NewCommandB a one line string?
Btw for completeness finalFileList.txt contains just file names one line after another:
I have a dataset of around 1000 lines. Out of these 1000 lines I need to pick randomly 160 lines of data and write it to a file. The program is needed to eliminate data bias when I run the program through a reanalysis program. I am thinking I need to use the rand or srand term, but I am having difficulty writing this in perl. I have to write it in perl, because the rest of my scripts for this project are in perl, so consistency is important. The data only consists of one column of the data (YYYYMMDDHHHH).
I'm reading "OReilly Learning Perl 5th Edition", and there are such words:Code:You can use an array element like $fred in every place? where you could use any other scalavariable like $fred.At the bottom of the page, it explains the ? like this:Code:The most notable exception is that the control variable of a foreach loop, which you?ll see later in this chapter, must be a simple scalar.Since Perl has the save-and-restore mechanism for the control variable, why an array element can't be used as the control variable
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?)