04-11-2002
Try:
eval value=\$$offset
9 More Discussions You Might Find Interesting
1. Shell Programming and Scripting
This is what I tried:
vara=${varb}_count
(( vara += 1 ))
Thanks for help (4 Replies)
Discussion started by: pa3be
4 Replies
2. Shell Programming and Scripting
I don't understand this, can anyone explain the evaluation logic used here, and I would really appreciate a general explanation for it.
----------------------
Here's the korn script:
--------------------
#! /usr/bin/ksh
if ]
then
echo true
else
echo false
fi
if (( 2 > 10 ))
then... (1 Reply)
Discussion started by: numstr
1 Replies
3. Shell Programming and Scripting
Can someone help me out here. I can't get this piece of code to work. i.e. $ALL_EVENTS does not get interpreted in the if brackets. The first part is the code, the second part is the execution of the code. Note: $ALL_EVENTS does equal 2, but there is no value once passed to the if statement. ... (4 Replies)
Discussion started by: jwholey
4 Replies
4. Shell Programming and Scripting
i need to output an ls command to a file but also capture any errors from that command and output them to a log file and the screen.
if it's only possible to output them to a log file and not the screen then that's fine.
this is what i've tried so far, but it won't populate log.txt. i've... (16 Replies)
Discussion started by: mjays
16 Replies
5. UNIX for Dummies Questions & Answers
Hi all.
So I have a problem. I have been doing real good figuring this stuff out on my own but Im a newbie and stuck on something that is probably real basic.
I want to get the following output from the who command:
User TTY Date Time
gd22a12 pts/1 Feb 1 11:34
gd22a13 pts/3 Feb 1... (13 Replies)
Discussion started by: losingit
13 Replies
6. Shell Programming and Scripting
I apologize for the title but I am not even sure myself what to call this. I am going to use an example of a pizza delivery. I need to make an interactive script that allows users to order a certain number of pizzas, and then choose what they want on each pizza. Here is my code so far....
... (1 Reply)
Discussion started by: cstadnyk1
1 Replies
7. Shell Programming and Scripting
Hi,
I had another question. I was wondering if there was a way to tab a line a variable number of times in tcsh. To go into details, I want to tab a line by how deep a file is in its path.
So here is an example code:
set filea=/blah1/blah2/blah3
set fileb=/blah1/blah2/blah3/blah4
set... (4 Replies)
Discussion started by: chu816
4 Replies
8. Shell Programming and Scripting
Hello all,
I would like to create a for loop or whatever is quick that will print the one’s place of a number for 1-N times
say for example a printed page formatting is 132 characters wide,
I would like a single line
123456789012345678901234567890... ...012
That is 132 characters long. I... (11 Replies)
Discussion started by: KmJohnson
11 Replies
9. UNIX for Dummies Questions & Answers
Hi
Please can you help how do I count the number of specific characters or words that appear in a file? (8 Replies)
Discussion started by: fretagi
8 Replies
eval(n) Tcl Built-In Commands eval(n)
__________________________________________________________________________________________________________________________________________________
NAME
eval - Evaluate a Tcl script
SYNOPSIS
eval arg ?arg ...?
_________________________________________________________________
DESCRIPTION
Eval takes one or more arguments, which together comprise a Tcl script containing one or more commands. Eval concatenates all its argu-
ments in the same fashion as the concat command, passes the concatenated string to the Tcl interpreter recursively, and returns the result
of that evaluation (or any error generated by it). Note that the list command quotes sequences of words in such a way that they are not
further expanded by the eval command.
EXAMPLES
Often, it is useful to store a fragment of a script in a variable and execute it later on with extra values appended. This technique is
used in a number of places throughout the Tcl core (e.g. in fcopy, lsort and trace command callbacks). This example shows how to do this
using core Tcl commands:
set script {
puts "logging now"
lappend $myCurrentLogVar
}
set myCurrentLogVar log1
# Set up a switch of logging variable part way through!
after 20000 set myCurrentLogVar log2
for {set i 0} {$i<10} {incr i} {
# Introduce a random delay
after [expr {int(5000 * rand())}]
update ;# Check for the asynch log switch
eval $script $i [clock clicks]
}
Note that in the most common case (where the script fragment is actually just a list of words forming a command prefix), it is better to |
use {*}$script when doing this sort of invocation pattern. It is less general than the eval command, and hence easier to make robust in |
practice. The following procedure acts in a way that is analogous to the lappend command, except it inserts the argument values at the
start of the list in the variable:
proc lprepend {varName args} {
upvar 1 $varName var
# Ensure that the variable exists and contains a list
lappend var
# Now we insert all the arguments in one go
set var [eval [list linsert $var 0] $args]
}
However, the last line would now normally be written without eval, like this: |
set var [linsert $var 0 {*}$args] |
SEE ALSO
catch(n), concat(n), error(n), interp(n), list(n), namespace(n), subst(n), tclvars(n), uplevel(n)
KEYWORDS
concatenate, evaluate, script
Tcl eval(n)