Hi,
Am trying to write a shell script which will append a header and a footer to an existing file. Header will contain details like the current date while the footer will contain the no: of records listed in the file.
I know we can use the CAT command, but i have no clue abt the syntax to... (4 Replies)
Hi, I am a newb as far as shell scripting and SED goes so bear with me on this one.
I want to basically append to each line in a file a delimiter character and the line's line number e.g
Change the file from :-
aaaaaa
bbbbbb
cccccc
to:-
aaaaaa;1
bbbbbb;2
cccccc;3
I have worked... (4 Replies)
It appears that this has been asked and answered in similar fashions previously, but I am still unsure how to approach this.
I have two files containing user information:
fileA
ttim:/home/ttim:Tiny Tim:632
ppinto:/home/ppinto:Pam Pinto:633
fileB
ttim:xkfgjkd*&#^jhdfh... (3 Replies)
A friend contacted me recently with an interesting question. We got something worked out, but I'm curious what answers you all can come up with.
Given a shell script (in bash) that processes a bunch of data and appends it to a file, how would you append the date, time, and a filename to the... (6 Replies)
Hi,
I have the following file,
ABC.txt:
ABC=123
DEF=234
FGH=345
Based on my validation and conditional processing it is observed that i need to comment or append # before DEF=234
so the same file ABC.txt should look as follows
ABC=123
#DEF=234
FGH=345
Sorry if its a... (6 Replies)
Hi,
My requirement is to append a date in format DDMMYYYYHHMISS at the end of first line of file which is HEADER. I am trying command
sed -i '1s/.*/&<date_format>/' <file_name>
Where <date_format>=`date +%m%d%Y%H%M%S`
I am somehow misisng the right quotes ti get this added in above... (2 Replies)
I'm working on a personal project, a multiplication quiz script for my kids. In it, the user's performance will be recorded and written to a file. After they've played it a little while, it will start to focus more on the ones that give them the most trouble-- that take a long time to answer or... (4 Replies)
Hi All,
I thinking on how to accelerate the speed on calculate the dat file against the number of records CTRL file.
There are about 300 to 400 folder directories that contains both DAT and CTL files.
DAT contain all the flat files records
CTL is the reference check file for the... (3 Replies)
First month learning about the Linux terminal and it has been a challenge yet fun so far. We're learning by using a gameshell. I'm trying to display a certain line ( only allowed 1 command ) from a file only using the head or tail. I'm pretty about this answer:
head -23 history.txt | tail -1... (1 Reply)
Discussion started by: forzatekk
1 Replies
LEARN ABOUT OSX
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)