Software :: Bash Shell - Export A Variable From A Script?
Jun 24, 2010
I need to be able to set a variable that is used by my build environment. I need to be able to change this variable "on the fly" as I work with multiple build environments. A portion of the variable is arbitrary, so I need to treat the arbitrary portion of the variable as an argument.
I would normally just create an alias, but BASH doesn't support arguments to aliases. So the workaround for the no-alias-arguments bug is to use a script. No problem. Except the variable I set in the script does not exist when I exit the script.Now, if I run the script by using "$ . myscript" it works in that the variable is set after it exits. The problem is the argument checking I have in the script doesn't work anymore. BASH aliases don't support arguments and I can't export a variable from a script unless I source the script (is it even a script at that point?) Maybe I am simply taking the wrong approach.
On one of my servers I see this when I log in. What does this mean and how can I get it to go away? Everything seems to work fine, but none of my other machines give this error.
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).
Is there any way to use "export" inside a bash script that will affect the variable in the parent process (i.e. the terminal where the script was run)?
I am a newbie to Linux. I tried setting environment variable using export JAVA_HOME=/usr/java/jdk1.6 but that was not permanent (i.e is was there for that terminal session). I want to know how can i set environment variable permanently in Fedora 13 just like we do in windows.After google search, some user suggested to edit bashrc and profile file for setting environment variables but above file contains some shell programs.
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.
Is there some type of functional way to read things in the Python shell interpreter similar to less or more in the bash (and other) command line shells?
Example:
Code:
>>> import subprocess >>> help(subprocess) ... [pages of stuff to read] ...
I'm hoping so as I hate scrolling and love how less works with simple keystrokes for page-up/page-down/searching etc.
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 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.
We have a file that declares many environmental variables. Out of which I have doubt on few. These variables are declared in UNIX environment. We are planing to migrate them along with applications to Linux.
Code: export MAILSERVER="%new@hub" MAIL_USERS="vinay.new"{MAILSERVER}",vijay.new"{MAILSERVER} Does the above declarations work in Linux ? The above declarations expands to Code: mail vinay.new%new@hub,vijay.new%new@hub which looks little wierd.
I have a application on linux , I can excute it in command line . but when I invoked it via CGI(perl) , it can not excute successfully , so I suspected that there is something different between SHELL and CGI environment , but I haven't figure out what the difference is .
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
#xwit -id $paintersMom -focus -raise #sleep 1 #xwit -id $paintersMom -warp 30 390 #// fill in command on tool bar #sleep 1 #xte 'mouseclick 1' #sleep 1 #xwit -id $canvasWin -warp 221 40 #// color selection #sleep 1 #xte 'mouseclick 1' #sleep 1 #xwit -id $canvasWin -warp "$(($X-150))" "$Y" #//location on pac man #sleep 1 #xte 'mouseclick 1' #sleep 1
#xwit -id $canvasWin -warp 62 44 #// selecting color black #sleep 1 #xte 'mouseclick 1' #sleep 1 #xwit -root -warp 62 120 #// selecting back to canvas #sleep 1 #xte 'mouseclick 1' #// color canvas black #sleep 1 #xwit -id $paintersMom -focus -raise #xwit -id $paintersMom -warp 27 108 #//click back to pencil #sleep 1 #xte 'mouseclick 1' #sleep 1 </code>
Here for example $paintersmom is would be in the drawing of pacman but I would also want to use it when I colored him in.. but I would want both processes in a different shell script.
I'm making a script I want to be able to just call (ie, rclick instead of ./rclick) where do I put it?
~/bin? /bin? /usr/bin?
Also, how do I pass a variable to the script (rclick 10 will rightclick 10 times) (Found, so simple... $1)Lastly, can I force it to run on CPU2? CPU1 is completley locked up if I run this on it... Or can I make it use less cpu cycles?
I heard (although I can't find any sources for proof) that the USER environment variable may not be set in a old Unix shells (maybe even some obscure shells as well). What is the probability that it won't be set?
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.
