Another technique:
Store the command first, put it into 'ticks'. A tick within ticks is escaped '\''.
When running the command "eval" lets pipes semicolons etc. work.
Hello all
I'm on SunOS5.9 and I'm trying to make the arrow keys work as in DOS ..get the previous command , etc .. I searched this site and got an answer. I pasted the following code to my .kshrc file in my home directory...It still does not seem to work ...Am I missing anything here ?
I'm... (5 Replies)
Hello,
I am new to this forum and relatively new to unix, but hope to become an expert soon!
My question is: How can I find out the execution time of a command that has already completed execution? More specifically, I launched a Python script to populate a PostgreSQL database on Suse... (2 Replies)
Guys,
In work we have just gotten a new HP 9000 server and I'm trying to set it up so that if I press <Up arrow> key I can see the command I typed in last(and press enter to run it again).
Can anyone advise how to set this up. One friend suggested I touch a file called .toucheditXXXX (I cant... (4 Replies)
We have a Solaris Server and I am acessing it through telnet to run various commands for my data validation like GREP, SED, AWK etc.
My requirement is how do i use the previous command that was executed. I tried the option 'ESC' and then 'k'. It displays the characters like '^[[A' etc. How do I... (0 Replies)
We have a Solaris Server and I am acessing it through telnet to run various commands for my data validation like GREP, SED, AWK etc.
My requirement is how do i use the previous command that was executed. I tried the option 'ESC' and then 'k'. It displays the characters like '^[[A' etc. How do I... (1 Reply)
We have a Solaris Server and I am acessing it through telnet to run various commands for my data validation like GREP, SED, AWK etc.
My requirement is how do i use the previous command that was executed. I tried the option 'ESC' and then 'k'. It displays the characters like '^[[A' etc. How do I... (2 Replies)
Hi All,
I would like to retrieve the whole command that got executed for a running process rather than a truncated string, as a result of running ps -ef on HP-UX.
Please help.
TIA (1 Reply)
Hi,
i would like to retrieve (only retrieve, not execute) a previous command which i executed on the command prompt. I tried the 'up arrow' key, but its not working. Instead,it showed me some funny characters. I searched around and i found the way to do it was using the way below. Several... (5 Replies)
Hi
I am trying to retrieve values from a tab-delimited file.I am using
while read record
value=`echo $record | cut -f12`
done
Where 12 is the column no i want retieve and record is one line of the file.
But it is returning the full record.
Plz help (4 Replies)
Discussion started by: akashtcs
4 Replies
LEARN ABOUT CENTOS
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)