Dear Folks,
I have a command output something like:
And I want to store PIN0 and SIG0 in two shell variables, now I do a double awk:
PIN=`gsmctl -d /dev/ttyS0 pin sig | awk '/PIN0/ { print $2}'`
SIG=`gsmctl -d /dev/ttyS0 pin sig | awk '/SIG0/ { print $2}'`
It's possible to... (4 Replies)
Hello,
I wonder if it is possible to pass and use variables from shell environment into sed or awk. I am trying to achieve something similar to the following using sed or awk:
var=some_regular_expression
grep "$var" filename # Will extract lines from filename
The following code,... (3 Replies)
meas is a shell variable, and this works perfectly fine for me:
awk -v var=$meas -F, '$1==var' /abcd/efgh.txt > temp1.csv
However, i want to introduce another shell variable, named, defnfile in the statement, in place of hardcoded path for efgh.txt like:
awk -v var=$meas -F, '$1==var'... (3 Replies)
Hello, I've been trying to figure out how to use variables inside the AWK command and use it back in the korn shell sript.
in my script I have lots of awk commands like this
grep Listen /etc/ssh/sshd_config | \
awk '{ if ($2 == "22" ) print "OK";
else print "not OK"
}'
... (3 Replies)
I apologize if this topic has been beaten to death here, but my limited searching skills did not throw up any results.
Here's what I am trying to accomplish
List all the files in a certain directory; assign the file names to an array which will be used later in the script.
My script looks like... (2 Replies)
Hello everybody:
I want to replace any field $2 of any file line (f.i. test.txt) matching $1 with a shell variable.
$ cat test.txt
F 0
B A
H -12.33
Now I'm going to ask the value of variable B:
$ SEARCHVAR=B
$ OLDVAL=$(awk -v SEARCHVAR="$SEARCHVAR"... (4 Replies)
Hello,
I have two files File1 & File2.
File1
76 135
136 200
250 345
....
File2
1 24
1 35
1 36
1 72
....
I want to get all the values form File2 corresponding to the range in File 1 and feed it to a program. Is the code below right? Can I pass shell variables to awk in this... (2 Replies)
Hi,
How could we take the value of awk variables out to shell?
I know the following methods
1. awk '{print $1}' < file | read a
echo $a
2. a=`awk '{print $1}' < file`
echo $a
Please let me know if there are any other methods.
Also, how do we take more than 1 variable value... (4 Replies)
Hi.
I need to parse file and assign some values to variables, right now i do like below
MYHOMEDIR=`awk '/Home/ {print $NF}' output.txt`
MYSHELL=`awk '/Shell/ {print $NF}' output.txt`
PRGRP=`awk '/Primary/ {print $NF}' output.txt`
SECGRP=`awk '/Second/ {print $NF}' output.txt`
In this... (10 Replies)
Hi All,
I have a file which I am reading and looking for "EXIT" statement. I want to insert ":JCWPROD" after each EXIT statement only if ":JCWPROD" doesn't exist.
Here is the sample file :
EXIT
Testing
EXIT
tesing123
EXIT
Desired file :
EXIT
:JCWPROD
Testing
EXIT
:JCWPROD... (7 Replies)
Discussion started by: nua7
7 Replies
LEARN ABOUT PHP
empty
EMPTY(3) 1 EMPTY(3)empty - Determine whether a variable is emptySYNOPSIS
bool empty (mixed $var)
DESCRIPTION
Determine whether a variable is considered to be empty. A variable is considered empty if it does not exist or if its value equals FALSE.
empty(3) does not generate a warning if the variable does not exist.
PARAMETERS
o $var
- Variable to be checked
Note
Prior to PHP 5.5, empty(3) only supports variables; anything else will result in a parse error. In other words, the follow-
ing will not work: empty(trim($name)). Instead, use trim($name) == false.
No warning is generated if the variable does not exist. That means empty(3) is essentially the concise equivalent to !isset($var)
|| $var == false.
RETURN VALUES
Returns FALSE if $var exists and has a non-empty, non-zero value. Otherwise returns TRUE.
The following things are considered to be empty:
o "" (an empty string)
o 0 (0 as an integer)
o 0.0 (0 as a float)
o "0" (0 as a string)
o NULL
o FALSE
o array() (an empty array)
o $var; (a variable declared, but without a value)
CHANGELOG
+--------+---------------------------------------------------+
|Version | |
| | |
| | Description |
| | |
+--------+---------------------------------------------------+
| 5.5.0 | |
| | |
| | empty(3) now supports expressions, rather than |
| | only variables. |
| | |
| 5.4.0 | |
| | |
| | Checking non-numeric offsets of strings returns |
| | TRUE. |
| | |
+--------+---------------------------------------------------+
EXAMPLES
Example #1
A simple empty(3) / isset(3) comparison.
<?php
$var = 0;
// Evaluates to true because $var is empty
if (empty($var)) {
echo '$var is either 0, empty, or not set at all';
}
// Evaluates as true because $var is set
if (isset($var)) {
echo '$var is set even though it is empty';
}
?>
Example #2
empty(3) on String Offsets
PHP 5.4 changes how empty(3) behaves when passed string offsets.
<?php
$expected_array_got_string = 'somestring';
var_dump(empty($expected_array_got_string['some_key']));
var_dump(empty($expected_array_got_string[0]));
var_dump(empty($expected_array_got_string['0']));
var_dump(empty($expected_array_got_string[0.5]));
var_dump(empty($expected_array_got_string['0.5']));
var_dump(empty($expected_array_got_string['0 Mostel']));
?>
Output of the above example in PHP 5.3:
bool(false)
bool(false)
bool(false)
bool(false)
bool(false)
bool(false)
Output of the above example in PHP 5.4:
bool(true)
bool(false)
bool(false)
bool(false)
bool(true)
bool(true)
NOTES
Note
Because this is a language construct and not a function, it cannot be called using variable functions.
Note
When using empty(3) on inaccessible object properties, the __isset() overloading method will be called, if declared.
SEE ALSO isset(3), __isset(), unset(3), array_key_exists(3), count(3), strlen(3), The type comparison tables.
PHP Documentation Group EMPTY(3)