In this case I'd say the same as i thought when i read the first post: there must have happened a serious flaw in the design process before to make such outrageous means necessary. This is the same as the old:
which should equally be avoided like the plague. Life is too short to waste it chasing evals once they go haywire (which the always do sooner or later).
Issue:
i have variable A which is an alias for variable B which is equal to "THIS IS A TEST"
when every i echo variable A i only get the alias name for variable B, NOT the contents of variable B.
HOSTNAME# echo $TESTIT
+ echo THIS IS A TEST
THIS IS A TEST
HOSTNAME# ls -l
total... (10 Replies)
Hi everyone,
I am trying to create a simple batch file to make SQL backups. this part of it works fine. Currently the script can mysql dump the databases, compress them, delete the .sql, compress the individual tar.gz into one larger one, delete the smaller files, encrypt the final tar.gz and... (1 Reply)
Hey folks,
I'm pretty new to unix programming. I was trying to get something to work but it's not doing what I expected.
#!/bin/ksh
. ./functions.sh
STRING=function_1
FUNCTION="$STRING"
RETURN=eval $FUNCTION
echo "value of $FUNCTION function is: $RETURN"
All i'm... (5 Replies)
Dear all,
I have basic knowledge of Unix script and her I am trying to process variable length and variable format CSV file.
The file length will depend on the numbers of Earnings/Deductions/Direct Deposits.
And
The format will depend on whether it is Earnings/Deductions or Direct Deposits... (2 Replies)
Hi all,
Hereby wish to have your advise for below:
Main concept is
I intend to get current directory of my script file.
This script file will be copied to /etc/init.d.
A string in this copy will be replaced with current directory value.
Below is original script file:
... (6 Replies)
echo "$previous_tmp$i"
I have a 5 variables like
previous1
previous2
previous3
previous4
previous5
I want to use a for loop to call them one by one.
How can I ?:confused: (2 Replies)
First post on here. So I use csh shells for my research (physics... not a CS person). I am trying to rerun the same scripts, but there are ~10 files that have similar variables that I have to change for each different configuration, so I would like one central file for the variables I change that... (3 Replies)
Hi everyone,
Is it possible to set a variable that calls another variable?
I.E.
SCRIPT=MY_SCRIPT.ksh ${VAR5}
${VAR5} is set earlier in the script, and I want to be able to call this when setting the ${SCRIPT} variable.
I hope this makes sense.
Thanks for your help. (3 Replies)
Hi all,
I have a source config file with variables like so:
eth1_ip=192.168.1.99
eth2_ip=192.168.1.123
eth3_ip=172.16.1.1
I am trying to run a script which loops based on the number of eth interfaces on a machine and therefore modifies the variable it calls in the environment based on the... (5 Replies)
I'm trying to do something like this:
find . -name blablabla -exec ln -s ./"{:53:14} blablabla" \;
The idea is find blablabla and create a symbolic link to it using part of it's path and then it's name, "blablabla."
I just don't know if I can call characters out of a find variable. ... (16 Replies)
Discussion started by: scribling
16 Replies
LEARN ABOUT MOJAVE
eval
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)