08-21-2008
10 More Discussions You Might Find Interesting
1. Shell Programming and Scripting
Hello all,
I need some help to create a script which contain a few strings on every line, and use those strings in a loop to fire some commands.
for exmaple the file looks like
tom
dave
bill
andy
paul
I want to read one line at a time and use it in loop like
command tom
command dave... (3 Replies)
Discussion started by: xboxer21
3 Replies
2. Shell Programming and Scripting
Guys,
I am trying to read the whole file using while loop but when i run the ssh part of the script it reads only the first line and exit after that.
There are in total 134 lines in the file, but when the output is redirected, it does only for one line and comes to command prompt.
pls help..... (11 Replies)
Discussion started by: sdosanjh
11 Replies
3. Shell Programming and Scripting
I know I should be able to see a way of doing this easily, but my brain just won't engage.
I have a script working on an embedded device that checks to see if an item is in a blacklist before performing some actions.
At the moment the code reads thus....
while read BLACKLIST ; do
... (7 Replies)
Discussion started by: Bashingaway
7 Replies
4. Shell Programming and Scripting
I have written a script to read the file line by line.
It is reading and printing the lines.
But it is coming out of loop before reading last line.
So I am not able to print last line.
How do I solve it. (6 Replies)
Discussion started by: dgmm
6 Replies
5. Shell Programming and Scripting
Hi,
I am reading file records inside a while loop,
and want to update the record when certain condition is met.
How can I update a file while being read?
I want to avoid using temporary files, copy, rename, ...
while IFS=',' read -r f1 f2
do
function(f1,f2)
if
then
<add... (1 Reply)
Discussion started by: ysrini
1 Replies
6. Shell Programming and Scripting
Hello,
I have a huge file, I am currently using while loop to read and do some calculation on it, but it is taking a lot of time.
I want to use AWK to read and do those calculations.
Please suggest.
currently doing:
cat input2 | while read var1
do
num=`echo $var1 | awk... (6 Replies)
Discussion started by: anand2308
6 Replies
7. Shell Programming and Scripting
Hi,
I have a variable which stores file names as a result of find command. I need to delete all these files one by one, i.e. by a loop. Can anyone tell me how can it be done?
The variable f2d has the file names like these
abc.txt
bcd.txt
fff.txt
gef.txt
Now I have used a loop as... (12 Replies)
Discussion started by: jhilmil
12 Replies
8. Shell Programming and Scripting
Hello,
I am using below code for reading from a file and assigning the values to a variable , but it is loosing the value after the loop , please suggest to retain the value of the variable after the loop ,
while IFS=: read -r line
do
set $dsc=$line
echo 'printing line variable ' $line... (1 Reply)
Discussion started by: ParthThakkar
1 Replies
9. Shell Programming and Scripting
I have a file1.txt with several 100k lines, each of which has a column 9 containing one of 60 "label" identifiers. Using an labels.txt file containing a list of labels, I'd like to extract 200 random lines from file1.txt for each of the labels in index.txt.
Using a contrived mini-example:
$ cat... (8 Replies)
Discussion started by: pathunkathunk
8 Replies
10. Shell Programming and Scripting
I have files named with different prefixes. From each I want to extract the first line containing a specific string, and then print that line along with the prefix.
I've tried to do this with a while loop, but instead of printing the prefix I print the first line of the file twice.
Files:... (3 Replies)
Discussion started by: pathunkathunk
3 Replies
foreach(n) Tcl Built-In Commands foreach(n)
__________________________________________________________________________________________________________________________________________________
NAME
foreach - Iterate over all elements in one or more lists
SYNOPSIS
foreach varname list body
foreach varlist1 list1 ?varlist2 list2 ...? body
_________________________________________________________________
DESCRIPTION
The foreach command implements a loop where the loop variable(s) take on values from one or more lists. In the simplest case there is one
loop variable, varname, and one list, list, that is a list of values to assign to varname. The body argument is a Tcl script. For each
element of list (in order from first to last), foreach assigns the contents of the element to varname as if the lindex command had been
used to extract the element, then calls the Tcl interpreter to execute body.
In the general case there can be more than one value list (e.g., list1 and list2), and each value list can be associated with a list of
loop variables (e.g., varlist1 and varlist2). During each iteration of the loop the variables of each varlist are assigned consecutive
values from the corresponding list. Values in each list are used in order from first to last, and each value is used exactly once. The
total number of loop iterations is large enough to use up all the values from all the value lists. If a value list does not contain enough
elements for each of its loop variables in each iteration, empty values are used for the missing elements.
The break and continue statements may be invoked inside body, with the same effect as in the for command. Foreach returns an empty string.
EXAMPLES
This loop prints every value in a list together with the square and cube of the value:
set values {1 3 5 7 2 4 6 8} ;# Odd numbers first, for fun!
puts "Value Square Cube" ;# Neat-looking header
foreach x $values { ;# Now loop and print...
puts " $x [expr {$x**2}] [expr {$x**3}]"
}
The following loop uses i and j as loop variables to iterate over pairs of elements of a single list.
set x {}
foreach {i j} {a b c d e f} {
lappend x $j $i
}
# The value of x is "b a d c f e"
# There are 3 iterations of the loop.
The next loop uses i and j to iterate over two lists in parallel.
set x {}
foreach i {a b c} j {d e f g} {
lappend x $i $j
}
# The value of x is "a d b e c f {} g"
# There are 4 iterations of the loop.
The two forms are combined in the following example.
set x {}
foreach i {a b c} {j k} {d e f g} {
lappend x $i $j $k
}
# The value of x is "a d e b f g c {} {}"
# There are 3 iterations of the loop.
SEE ALSO
for(n), while(n), break(n), continue(n)
KEYWORDS
foreach, iteration, list, looping
Tcl foreach(n)