You got it - almost - right, but still wrong. ;-))
Here is how "variable expansion" (this is how the process is called) works:
if you prepend a string with the dollar sign ("$"), the string will be interpreted as name of a variable and the name will be replaced by the content of the variable. Example:
This will replace the string "$myvar" with the content of the variable "myvar" and then execute the echo-command with it.
Note that you do NOT need this "expansion" when you assign a variable! Hence:
Also notice, that this expansion notation is a shortcut: the complete construct is to enclose the name in curly braces. The following illustrates this:
Now, that leaves the question of how to assign one variable with the content of another. Can you guess it?
A word about quoting: you will notice that i enclosed the assignment into double quotes. This is because the shell automatically splits at word boundaries. This would be what happens without quoting:
The shell would assign "multiple" to the variable "myvar" and be left over with the word "words", which would lead to an error message, because it simply makes no sense. The same with
First the shell would replace "$myvar" with the content of the variable "myvar" ending with this line:
and here what i said above applies. This is why you need quoting, which is a bigger topic in itself, so i am cutting it short here. Just ask if you would like to know more about this.
Also notice that expansion is not limited to simple expanding to the unaltered content. It is also possible to change on the expanded content of the variable:
and so on. I suggest a good book about shell programming for this.
I have a program to create a directory if not present. Here is the program.
FYI: Directory name format: YYYY_MM_DD
#!/bin/bash
date=`date +%Y_%m_%d`
presence=$(ls -lrt /TS_File/ | grep "$date" | awk '{print $9}')
if
then
mkdir /TS_File/$date
else
echo "Unable to Create... (5 Replies)
In my script I'm retrieving a parameter through an API call. I need to trim some things out of the result so I can use it as a parameter to pass to another process. I've got it working but it's pretty kludgy and I'm hoping someone can help me with a better way.
This is the code that retrieves... (2 Replies)
Hi,
The following assigment is not working within shell script but is working from command line. Could anybody advise why? OS - solaris 8
APPL=`grep "$Application" ldapapps |awk '{print $1}'`
echo $APPL (5 Replies)
I'm going freakin crazy here! I've tried multiple attempts and configurationa and cannot get this to work.
I have a file:
private/etc/apt/sources.list.d/cydia.list
I want to replace a string in this file:
"deb http:name.of.address ./"
with
"deb http:name.of.other.address ./"
The... (4 Replies)
Hy friends, I am newbie to bash scripting, can anyone explain how b=${a/23/BB} # Substitute "BB" for "23". this line converts "b" into string and and "d" into Integer. Thanks in advance (4 Replies)
Hello All,
I'm trying to assign integer values to variables using substitution in both the value and variable's name, i.e.,
number$x=$x
where x is equal to one in the first assignment, two in the second assignment, and so on with x being incremented each time.
However, when I do the... (7 Replies)
If i'm given a string like "abc-def-1.2.3", how would I return "1"? I'm new to scripting and got stumped on this problem. Thanks in advance! (7 Replies)
Sorry for my english i am french
So i am receiving from a script this prompt :
tabular;critical;mirroring;DG INTlocaldg VOLUME appears
tabular;critical;mirroring;DG INTlocaldg VOLUME bh3vm
tabular;critical;mirroring;DG INTlocaldg VOLUME dev
tabular;critical;mirroring;DG INTlocaldg VOLUME... (3 Replies)
I figured this forum needs some laughs , so I am posting this.
And if the answer is - it depends on bash version - do not reply.
This is from "manual"
while CONTROL-COMMAND; do CONSEQUENT-COMMANDS; done
And here is the REAL code - no ";"
while do xterm & i=$ done (2 Replies)
Hi,
I am new in bash scripting. In my work, I provide support to several users and when I connect to their computers I use the same admin and password, so I am trying to create a script that will only ask me for the IP address and then connect to the computer without having me to type the user... (5 Replies)