05-20-2015
Using a pipe puts the loop into a subshell. Any variable changes inside it aren't reflected outside the loop, and once the loop finishes, the subshell ceases to exist. It's kind of like the difference between running a script and sourcing it.
It's also a good reason to get out of the habit of
useless use of cat.
Last edited by Corona688; 05-20-2015 at 04:39 PM..
This User Gave Thanks to Corona688 For This Post:
10 More Discussions You Might Find Interesting
1. Shell Programming and Scripting
Hello everyone,
how can I send output to the screen from a running script or tcl, in such a way that if a loop is executing I will see the rolling counter on my screen as the records are processed in the loop. I do not want the screen to scroll, though. In other words can a var's value be painted... (2 Replies)
Discussion started by: lifespan
2 Replies
2. Shell Programming and Scripting
Say I have (in psuedocode)
For i=1 to 10
tar cvfb /... 5*i /junk(i)
end
What I mean is that I want each successive for loop to have the block size parameter be 5 times the current counter. This isn't my actual code, just a stupid example...So the question is how do I descrive that parameter... (2 Replies)
Discussion started by: jeriryan87
2 Replies
3. Homework & Coursework Questions
1. The problem statement, all variables and given/known data:
Variable is resetting to 0 after incrementing in while loop
My bit of scripting displays the current users logged in the machine.
Then it reads in a specific username and displays the processes for that user.
The portion that I... (3 Replies)
Discussion started by: ratzlaff
3 Replies
4. Shell Programming and Scripting
Hi,
hope I am posting in the right section.
My problem is that I have 2 or more arguments passed and I want to check if the arguments passed exists or not.
The first argument should not exist and the remaining others should exist.
example:
./shells.sh argument1 argument2 argument3
... (5 Replies)
Discussion started by: fight4love
5 Replies
5. Shell Programming and Scripting
Hello Everyone,
I'm in need of assistance on creating a script with a counter on a certain string.
Basically this script opens a log file and displays certain log data. There are two key words in the log. START and FINISH. In between the START and FINISH is a variable ACTNUMBER. It will... (1 Reply)
Discussion started by: rxc23816
1 Replies
6. Shell Programming and Scripting
hello,
File 1
main Group sub group
MIT VAR_1D_DATA_TYPE 23-03-2012
MIT VAR_1D_DATA_TYPE 22-03-2012
MIT VAR_10D_DATA_TYPE 23-03-2012
MIT VAR_10D_DATA_TYPE 22-03-2012
MIT ... (0 Replies)
Discussion started by: manas_ranjan
0 Replies
7. Shell Programming and Scripting
Hi,
I am working on a script where I need to add one functionality i.e. to could the number of tar files at particular location...but the script is working in below way.
1) create sandbox
2) Drop old member function
3) addmember function
4) Apply checkpoint lable
5) Resync operation(This... (1 Reply)
Discussion started by: anuragpgtgerman
1 Replies
8. Homework & Coursework Questions
Use and complete the template provided. The entire template must be completed. If you don't, your post may be deleted!
1. The problem statement, all variables and given/known data:
The program is supposed to read in text from a given file ( different samples provided in the homework but not... (1 Reply)
Discussion started by: c++newb
1 Replies
9. Shell Programming and Scripting
Hi friends, I just want to try some thing with shell using loop and counter
I have 30 Directory, in each directory number of files say 5, 10, 20 etc...
directory_1
directory_2
directory_n
what I want to do is read files from directory_1 say 5 files
if my counter is like this
m=2000 ... (6 Replies)
Discussion started by: Akshay Hegde
6 Replies
10. Shell Programming and Scripting
#!/usr/bin/ksh
c=0
while ]; do
echo /tmp/unex NOT found, iter : $c;
((c = $c + 1));
sleep 2;
done
so, the above counter doesn't work, already tried both -lt & -gt, and changed || to &&
so what am I missing?
Thanks in advance (5 Replies)
Discussion started by: unexistance
5 Replies
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)