11-13-2010
Brilliant - thanks pludi. I thought I'd tried this previously and couldn't get it working, so eval was a clutch at straws. The description and example on the link were invaluable.
Jerry
10 More Discussions You Might Find Interesting
1. Shell Programming and Scripting
Say I write something like the following:
var1=1
var2=2
for int in 1 2
do
echo "\$var$int"
done
I want the output to be:
1
2
Instead I get something like:
$var1
$var2 (2 Replies)
Discussion started by: Awanka
2 Replies
2. UNIX for Dummies Questions & Answers
Hello,
Could you please let me know what is the problem here..
28:var1="SERVER_$j"
29:eval $var1=`grep "^DBSERVER=" "$i" |cut -d"=" -f2`
i get this error:
syntax error at line 29 : `|' unexpected
Thanks for your quick response..This is urgent..pls..
Regards
Kaushik (5 Replies)
Discussion started by: kaushikraman
5 Replies
3. Programming
Hello everybody,
I am having problem in converting byte array variables to Hexa String variables for Linux. I have done, converting byte array variables to Hexa String variables for Windows but same function doesn't work for linux. Is there any difference in OS ? The code for Windows is given... (2 Replies)
Discussion started by: ritesh_163
2 Replies
4. Shell Programming and Scripting
Dear All,
I have one problem in my script, awk statement as
1. it is not evaluate the second variable $stake but the first one $channel is being done.
2.I want to assign the whole awk statement to a variable actual_code which is not being executed in my script.
#!/usr/bin/sh
echo "Enter... (3 Replies)
Discussion started by: chinmayadalai
3 Replies
5. Shell Programming and Scripting
Hi everybody, I need the help of the Unix community once again :)
I have some code which queries an XML feed and displays the results for me. I would like to enter the XML output in to my database, but I am having trouble passing the variables while INSERTing.
Here is my code that I need to... (0 Replies)
Discussion started by: o0110o
0 Replies
6. Shell Programming and Scripting
Hello everyone,
I've been looking how to pass variables between bash and php-cli in 1 file. So far i got this:
#!/bin/bash
echo "This is bash"
php << EOF
<?php
echo "This is php\n";
?>
EOF
I would now like to be able to pass a variable declared in the bash to the php. I already... (0 Replies)
Discussion started by: robbee
0 Replies
7. Shell Programming and Scripting
I have made a script that requires another php script for functions.
I need a way so that the required script can read and write the main script's variables.
Best Regards, John Wei
---------- Post updated at 08:54 AM ---------- Previous update was at 08:40 AM ----------
Sorry Guys, EDIT: my... (1 Reply)
Discussion started by: johntzwei
1 Replies
8. Shell Programming and Scripting
Hi All,
i have a requirement where i have to run a script with at least 25 arguements and position of arguements can also change. the unapropriate way is like below. can we achieve this in more good and precise way??
#!/bin/ksh
##script is sample.ksh
age=$1
gender=$2
class=$3
.
.
.... (3 Replies)
Discussion started by: Lakshman_Gupta
3 Replies
9. Shell Programming and Scripting
Trying to do so
echo "111:222:333" |awk -F: '{system("export TESTO=" $2)}'But it doesn't work (2 Replies)
Discussion started by: urello
2 Replies
10. Shell Programming and Scripting
greetings,
pretty new to php and i think i might be missing some fundamental limitation of isset. i have two php scripts below that are executed by crond, one using --host X and one that does not. and below that are three different attempts at generating a command line that will be executed. the... (8 Replies)
Discussion started by: crimso
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)