#!/bin/sh
##apple soda
##banana split
##peach cobbler
##apple pie
##apple computer
##zuchinni casserole
##mango apple smoothie
##adam's apple
##app installer
##whatsapp
##application manager
export me=$0
datacmd="cat $me | grep ^##"
echo $datacmd
data=`$datacmd`
output:
Code:
beomagi@VBMagi ~ $ ./test.sh
cat ./test.sh | grep ^##
cat: |: No such file or directory
cat: grep: No such file or directory
cat: ^##: No such file or directory
The first line of the output
"cat ./test.sh | grep ^##" is from the line echo $datacmd
The next 3 lines of errors all come from this : data=`$datacmd`
Yet if I directly drop this into the prompt:
Code:
beomagi@VBMagi ~ $ cat ./test.sh | grep ^##
##apple soda
##banana split
##peach cobbler
##apple pie
##apple computer
##zuchinni casserole
##mango apple smoothie
##adam's apple
##app installer
##whatsapp
##application manager
It works.
i.e. cat ./test.sh | grep ^## works,
BUT if it's a in a string type variable and I execute it as a system call it barfs.
Why?
---------- Post updated at 09:33 PM ---------- Previous update was at 09:14 PM ----------
I'm balder now.
I think that helped.
I found out that there's "eval" and I can even call bash if i want to execute my string.
backticks just don't seem to cut it for complex calls.
Code:
#!/bin/sh
##apple soda
##banana split
##peach cobbler
##apple pie
##apple computer
##zuchinni casserole
##mango apple smoothie
##adam's apple
##app installer
##whatsapp
##application manager
datacmd="cat $me | grep ^##"
echo $datacmd
data=`eval "$datacmd"`
echo "$data"
gives:
Code:
beomagi@VBMagi ~ $ ./test.sh
cat ./test.sh | grep ^##
##apple soda
##banana split
##peach cobbler
##apple pie
##apple computer
##zuchinni casserole
##mango apple smoothie
##adam's apple
##app installer
##whatsapp
##application manager
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Discussion started by: VSSajjan
2 Replies
LEARN ABOUT PHP
array_unshift
ARRAY_UNSHIFT(3) 1 ARRAY_UNSHIFT(3)array_unshift - Prepend one or more elements to the beginning of an arraySYNOPSIS
int array_unshift (array &$array, mixed $value1, [mixed $...])
DESCRIPTION array_unshift(3) prepends passed elements to the front of the $array. Note that the list of elements is prepended as a whole, so that the
prepended elements stay in the same order. All numerical array keys will be modified to start counting from zero while literal keys won't
be touched.
PARAMETERS
o $array
- The input array.
o $value1
- First value to prepend.
RETURN VALUES
Returns the new number of elements in the $array.
EXAMPLES
Example #1
array_unshift(3) example
<?php
$queue = array("orange", "banana");
array_unshift($queue, "apple", "raspberry");
print_r($queue);
?>
The above example will output:
Array
(
[0] => apple
[1] => raspberry
[2] => orange
[3] => banana
)
SEE ALSO array_shift(3), array_push(3), array_pop(3).
PHP Documentation Group ARRAY_UNSHIFT(3)
03-09-2015
