Hi, experts.
Whould anybody clear explay me difference and usage of these 3 commands (particulary in bash) :
exec
eval
source
I've tryed to read the manual pages but did not get much.
Also could not get something useful from Google search - just so much and so not exactly, that is... (3 Replies)
Hi,
I use AIX (ksh) and Linux (bash) servers. I'm trying to do scripts to will run in both ksh and bash, and most of the time it works. But this time I don't get it in bash (I'm more familar in ksh).
The goal of my script if to read a "config file" (like "ini" file), and make various report.... (2 Replies)
Dear all,
I have been working with Linux for quite few years but never required to learn Bash and Linux really dep doan.
I want to learn bash I bought books and Have been reading on the Internet but I cannot find my answers, maybe I am blind.
For example:
What does this means?
# for i in... (4 Replies)
I'm trying to understand if it's possible to create a set of variables that are numbered based on another variable (using eval) in a loop, and then call on it before the loop ends.
As an example I've written a script called question (The fist command is to show what is the contents of the... (2 Replies)
Hi everyone,
I have some questions regarding bash and my initializer files:
when I look at my bashrc file, I see lots of "export".. export MAGICK_HOME="$HOME/bin..etc".. what does export really mean?
in my bashrc, I have a line: "umask 0002" ... what does that do?
I have a bash_profile... (6 Replies)
Hi all
Sorry for the basic question, but i am writing a shell script to get around a slightly flaky binary that ships with one of our servers. This particular utility randomly generates the correct information and could work first time or may work on the 12th or 100th attempt etc !.... (4 Replies)
I have a text file called file1 which contains the text: "ls -l"
When I enter this command:
bash < file1 > file1
file1 gets erased. However if I enter this command:
bash < file1 > newfile
the output from "ls -l" is stored in newfile. My question is why doesn't file1's text ("ls -l") get... (3 Replies)
Hi Folks,
I know on one side there is script and on another side there is smart script. I am able to achieve what I got but thought there has to be a code which doesn't require multiple lines. So if you guys can help me out than it will be awesome. Also I wrote in cshell but if can get both the... (4 Replies)
Good evening all I have what might be a simple problem to solve but I do not know how to solve it myself. I am writing a bash script and my code looks something like this:
mp3=`ls | grep \.mp3`
for f in $mp3
do
echo $f
done
Basically what I want to do is look through the current... (4 Replies)
I am still learning shell scripting. Recently I see a function for read configuration. But some of special character make me confused. I checked online to find answer. It was not successful. I post the code here to consult with expert or guru to get better understanding on these special characters... (3 Replies)
Discussion started by: duke0001
3 Replies
LEARN ABOUT OPENDARWIN
while
while(n) Tcl Built-In Commands while(n)
__________________________________________________________________________________________________________________________________________________NAME
while - Execute script repeatedly as long as a condition is met
SYNOPSIS
while test body
_________________________________________________________________DESCRIPTION
The while command evaluates test as an expression (in the same way that expr evaluates its argument). The value of the expression must a
proper boolean value; if it is a true value then body is executed by passing it to the Tcl interpreter. Once body has been executed then
test is evaluated again, and the process repeats until eventually test evaluates to a false boolean value. Continue commands may be exe-
cuted inside body to terminate the current iteration of the loop, and break commands may be executed inside body to cause immediate termi-
nation of the while command. The while command always returns an empty string.
Note: test should almost always be enclosed in braces. If not, variable substitutions will be made before the while command starts execut-
ing, which means that variable changes made by the loop body will not be considered in the expression. This is likely to result in an
infinite loop. If test is enclosed in braces, variable substitutions are delayed until the expression is evaluated (before each loop iter-
ation), so changes in the variables will be visible. For an example, try the following script with and without the braces around $x<10:
set x 0
while {$x<10} {
puts "x is $x"
incr x
}
SEE ALSO
break(n), continue(n), for(n), foreach(n)
KEYWORDS
boolean value, loop, test, while
Tcl while(n)