08-22-2008
Quote:
Originally Posted by
royalibrahim
I still could not understand about the 'pattern value' or 'pattern space' concept. What happens if we change 1 as 2 in the above awk command?
The pattern is an expression that is evaluated for each record. If the result is
true the action statements are executed.
If the result of the evaluation is a string or a number, the empty string "" and the number zero are considered to be
false, all other values are
true.
So the patterns
1 and
2 gives the same result that is
true.
Jean-Pierre.
9 More Discussions You Might Find Interesting
1. UNIX for Dummies Questions & Answers
Write unix command to list or view auto links (0 Replies)
Discussion started by: ashishshah.engg
0 Replies
2. Shell Programming and Scripting
Hi All,
I am tring to set a shedule for cron to execute my script in every 15 min, n want a mail alert on my mail id if cron fails to get data as input for my script, how can i set that?
Thanks in advance
Subin (1 Reply)
Discussion started by: subin_bala
1 Replies
3. UNIX for Dummies Questions & Answers
Hi ,
I m beginner for Unix and i want to use FIFO in my 2 Scripts . I want 1 script to read data from FIFO and other will write into FIFO.
Despite reading so many articles/posts i am still unable sunchronize my scripts.
My doubts are
1> Do We require both scripts as daemons to use... (0 Replies)
Discussion started by: Akshay
0 Replies
4. UNIX for Dummies Questions & Answers
Hi All,
1. how and who calls .profile when you login
2. what is PPID and what means by PPID = 0
Thanks in Advance (2 Replies)
Discussion started by: ravi.sadani19
2 Replies
5. Shell Programming and Scripting
Hi,
I have 3 doubts which I posted it here.
Doubt 1:
I have a file containing data:
22 -73 89 10
99 21 15 -77
23 63 -80 91
-22 65 28 97
I am trying to print the fields in the reverse order and replace every field by its absolute (positive) value
(ie.) I am looking for output:
10... (8 Replies)
Discussion started by: royalibrahim
8 Replies
6. Shell Programming and Scripting
Hi everyone,
I read some shell script code,then I have some issue.
the following code.
let "t1 = ((5 + 3, 7 - 1, 15 - 4))"
echo "t1 = $t1"
t1=11
Here t1 is set to the result of the last operation.why? (3 Replies)
Discussion started by: luoluo
3 Replies
7. Shell Programming and Scripting
Hi,
I am having the following doubts on awk. Please clarify for me.
a) What does it mean?
awk '$1=$1' and how does it change if I append FS="" to the above code?
b) What if I use awk -vFS="\n" (i.e) setting (input) field separator to newline char, then what will be the value of $0,... (6 Replies)
Discussion started by: royalibrahim
6 Replies
8. HP-UX
Hello,
I'm new to HP-UX and I'm not sure about some concepts related to resizing fs's under this OS.
First of all I'm only asking about resizing ONLINE, it means, without having to umount the fs nor rebooting, etc.
Q1. I've read that in order to resize a fs online there are 2 requirements:... (3 Replies)
Discussion started by: asanchez
3 Replies
9. UNIX for Dummies Questions & Answers
well i have some doubts about the use of this commands:
my first doubt is to know if there is a way to execute a awk program from a file? (now i do copy paste, i copy the script of a notepad on the terminal and then i press enter, but i want to put this scripts in some folder and execute them)... (3 Replies)
Discussion started by: matius_88
3 Replies
if(n) Tcl Built-In Commands if(n)
__________________________________________________________________________________________________________________________________________________
NAME
if - Execute scripts conditionally
SYNOPSIS
if expr1 ?then? body1 elseif expr2 ?then? body2 elseif ... ?else? ?bodyN?
_________________________________________________________________
DESCRIPTION
The if command evaluates expr1 as an expression (in the same way that expr evaluates its argument). The value of the expression must be a
boolean (a numeric value, where 0 is false and anything is true, or a string value such as true or yes for true and false or no for false);
if it is true then body1 is executed by passing it to the Tcl interpreter. Otherwise expr2 is evaluated as an expression and if it is true
then body2 is executed, and so on. If none of the expressions evaluates to true then bodyN is executed. The then and else arguments are
optional "noise words" to make the command easier to read. There may be any number of elseif clauses, including zero. BodyN may also be
omitted as long as else is omitted too. The return value from the command is the result of the body script that was executed, or an empty
string if none of the expressions was non-zero and there was no bodyN.
EXAMPLES
A simple conditional:
if {$vbl == 1} { puts "vbl is one" }
With an else-clause:
if {$vbl == 1} {
puts "vbl is one"
} else {
puts "vbl is not one"
}
With an elseif-clause too:
if {$vbl == 1} {
puts "vbl is one"
} elseif {$vbl == 2} {
puts "vbl is two"
} else {
puts "vbl is not one or two"
}
Remember, expressions can be multi-line, but in that case it can be a good idea to use the optional then keyword for clarity:
if {
$vbl == 1 || $vbl == 2 || $vbl == 3
} then {
puts "vbl is one, two or three"
}
SEE ALSO
expr(n), for(n), foreach(n)
KEYWORDS
boolean, conditional, else, false, if, true
Tcl if(n)