Strange result of eval, how does eval really work with ssh?
Hi all,
some small script with eval turned me to crazy.
my OS is linux
below script works well
below script works also well
then below script has issue that only first line of command got executed
i was thinking maybe eval break the loop, but below script do print out the "-----" line
so what wrong here, please kindly help.
Last edited by summer_cherry; 05-04-2011 at 06:26 AM..
Reason: wrong title
Hi everyone,
I do have the requirement to store the value of below result in a variable
eval echo $a
Please .... Help me , it's urgent to my sript
Thanks in advance... (1 Reply)
Hi All,
I'm running some encrypted data through a script I wrote. In order to do this, I'm using eval to resolve some of my variables. At the moment, when I use eval to resolve, it strips out some of my encrypted values, and totally drops some others. For example if I have the value ab1"3 it drops... (1 Reply)
I am trying to expand the variable $user in my alias command and tried
several variations of eval but can't seem to get it to work.
The end result should be either:
oracle_user='sudo su - oracle ' or oracle_user='sudo su - oracle1 '
user=$(grep '^oracle:' /etc/passwd | cut... (5 Replies)
hi all,
Am trying to add some code to a ksh script and i dont understand how an eval function is used :
_var=$1
_conceal=$2
eval _val=\$${_var}
can someone shed some light on what the eval function in the above context means/does ??
thanks. (4 Replies)
my script
grep -v "^#" ${AP_Config}/masklist_new.txt | while read system maskleft maskright folder_prd floder_uat datetype Region
do
if ]; then
folder_env="prd"
else
folder_env="uat"
fi
targetfolder=${system}/eval echo... (3 Replies)
Hello All,
Since my variables are nested I use eval to populate the data.
I have an ambiguity here when eval is used along with &
say I have the below variable
url="www.unix.com" , this come from function call as argument.
I want to take this into another variable say... (6 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)