Difference between echo `ls -l` and echo "`ls -l`" ?
Hi guys,
Been messing around with shell programming for a couple of days and I found something that was pretty odd in the behavior of the echo command. Below is an example-:
When I type the following in my /home directory from my lxterminal in Debian-:
Now this is what I expected. I know whatever is put in ` ` is suppose to interpreted as a command in the BASH echo. So, therefore this is the expected output of ls -l on my /home directory.
But it gets weird when I remove the " " (double quotes) from the echo statement.
If you look closely you will see that it is exactly identical to the output that is given above except for the fact that it contains no line breaks. My question is why ?
Why are the line-breaks removed when I remove the double quotes from echo ? Whatever is there in ` `(tild signs) is supposed to be interpreted as a command right ?
If removal of double quotes " " means that there is a change in the meaning of the echo, then please tell me what is the special meaning that double quotes has in echo ?
Is there any difference between echo "$SHELL" and echo $SHELL ? I know the output is same but since one has double quotes and one doesn't is there any difference in the way that BASH treats them internally ?
I am using Debian Wheezy LXDE with Bash 4.2.
Thanks.
Hi,
I've modified the syslogd source to include a thread that will keep track of a timer(or a timer thread). My intention is to check the file size of /var/log/messages in every one minute & if the size is more than 128KB, do a echo " " > /var/log/messages, so that the file size will be set... (7 Replies)
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{ while true; do echo string; sleep 1; done } | read line This waits one second and returns.
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Hello All
Nice to meet you all here in this forum,
it's my 1rst time here
i'm asking about a little issue that i face
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the script is working fine with normal telnet
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echo `echo ` doesn't echoes anything. And it's logic. But
echo `echo `echo ` ` does echoes "echo". What's the logic of it? the `echo `echo ` inside of the whole (first) echo, echoes nothing, so the first echo have to echo nothing but echoes "echo"
(too much echoing :P):o (2 Replies)
Hello,
On a HP-UX 10.20 server I've executed something similar to this command:
# echo 'selall;info;wait;infolog;view;done' | /usr/sbin/cstm
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I suppose there is a way to fix it by using xargs but I can't figure it out.
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Hello, I have a simple(I think) question!
Although simple, I have been unable to resolve it, so I hope someone can help! OK, here it is:
1)I have an awk script that prints something, such as:
awk '{print $2}' a > x
so x might hold the value of say '10'
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Hi guys,
I have a shell script where I have the following:
for i in ad0 ad1
do
gpart create -s gpt $i || echo "Cannot create GPT partition on "$i". Exiting ..."
gpart add -s 128 -t freebsd-boot $i || echo "Cannot add freebsd-boot partition on "$i". Exiting ..."
gpart add -s 4G -t... (2 Replies)
Hi Folks,
As per the subject, the following command is not working as expected.
echo $variable | mail -s "subject" "xxx@xxx.com"
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I came across and unexpected behavior with redirections in tcsh. I know, csh is not best for redirections, but I'd like to understand what is happening here.
I have following script (called out_to_streams.csh):
#!/bin/tcsh -f
echo Redirected to STDOUT > /dev/stdout
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Discussion started by: marcink
2 Replies
LEARN ABOUT PHP
mssql_field_seek
MSSQL_FIELD_SEEK(3)MSSQL_FIELD_SEEK(3)mssql_field_seek - Seeks to the specified field offsetSYNOPSIS
bool mssql_field_seek (resource $result, int $field_offset)
DESCRIPTION
Seeks to the specified field offset. If the next call to mssql_fetch_field(3) won't include a field offset, this field would be returned.
PARAMETERS
o $result
- The result resource that is being evaluated. This result comes from a call to mssql_query(3).
o $field_offset
- The field offset, starts at 0.
RETURN VALUES
Returns TRUE on success or FALSE on failure.
EXAMPLES
Example #1
Using mssql_field_seek(3) on the example for mssql_fetch_field(3)
<?php
// Connect to MSSQL and select the database
mssql_connect('MANGOSQLEXPRESS', 'sa', 'phpfi');
mssql_select_db('php');
// Send a select query to MSSQL
$query = mssql_query('SELECT * FROM [php].[dbo].[persons]');
// Construct table
echo '<h3>Table structure for 'persons'</h3>';
echo '<table border="1">';
// Table header
echo '<thead>';
echo '<tr>';
echo '<td>Field name</td>';
echo '<td>Data type</td>';
echo '<td>Max length</td>';
echo '</tr>';
echo '</thead>';
// Dump all fields
echo '<tbody>';
for ($i = 0; $i < mssql_num_fields($query); ++$i) {
// Fetch the field information, notice the
// field_offset parameter is not set. See
// the mssql_field_seek call below
$field = mssql_fetch_field($query);
// Print the row
echo '<tr>';
echo '<td>' . $field->name . '</td>';
echo '<td>' . strtoupper($field->type) . '</td>';
echo '<td>' . $field->max_length . '</td>';
echo '</tr>';
// Move the internal seek pointer to the next
// row in the result set
mssql_field_seek($query, $i + 1);
}
echo '</tbody>';
echo '</table>';
// Free the query result
mssql_free_result($query);
?>
SEE ALSO mssql_fetch_field(3).
PHP Documentation Group MSSQL_FIELD_SEEK(3)