Friends,
I did following exercise
$ echo '' > test
$ od -b test
$ echo "">test
$ od -b test
$echo > test
$od -b test
Every time I got the following output
0000000 012
0000001
But 012 is octal value for new line character .
Even though there is no apperent new line character... (6 Replies)
Hello. I'm a complete newbie to C programming. I have a C program that wasn't written by me where I need to write some wrappers around it to automate and make it easier for a client to use. The problem is that the program accepts standard input to control the program... I'm hoping to find a simple... (6 Replies)
Hi Guys,
I've been learning UNIX for the past couple of days and I came across this exercise, I can't get my head around it, so I would be ever so grateful if I could receive some sort of help or direction with this.
Create a file with x amount of lines in it, the content of your choice. ... (3 Replies)
Hi,
Please don't berate me over the simplicity of these questions. I have recently gotten into bash shell scripting and enjoy it quite a bit. One thing I have not found the answer to though is when naming a shell script, what extension is normally used (ie myscript.?)? Also where is the standard... (5 Replies)
I had a script in solaris wich i read data, for example:
Number 1: _
and the cursor use to be in '_' place because in the code of the script i write:
echo "Number 1:\c"
but i copy the script to a linux and the cursor 'jump' to the begining of the next line like:
Number 1:... (2 Replies)
hi everybody;
trying to c unix programming and ive stucked with a problem:
simple program
filedr=open("tempfile",O_RDWR|O_TRUNC,0);
write(filedr,msg1,6);
int i;
i=read(filedr,msg3,4);
it returns 0 bytes read ... why?
well if i try to poll() before read , it doesnt indicate POLLHUP or... (4 Replies)
I am having trouble making this statement work. I am passing in a number value for the number of days to keep archive logs for and wanted to make sure that it is a number. I have a script that will return 1 for is a number and 0 for is not a number. I also want to make sure that the number is not... (2 Replies)
Cheers!
In /etc/syslog.conf, if an error type is not specified, is it logged anywhere (most preferable is it logged to /var/log/messages) or not?
To be more precise I am interested in error and critical level messages. At default these errors are not specified in syslog.conf, and I need to... (6 Replies)
Discussion started by: dr1zzt3r
6 Replies
LEARN ABOUT X11R4
escape
escape(1) Mail Avenger 0.8.3 escape(1)NAME
escape - escape shell special characters in a string
SYNOPSIS
escape string
DESCRIPTION
escape prepends a "" character to all shell special characters in string, making it safe to compose a shell command with the result.
EXAMPLES
The following is a contrived example showing how one can unintentionally end up executing the contents of a string:
$ var='; echo gotcha!'
$ eval echo hi $var
hi
gotcha!
$
Using escape, one can avoid executing the contents of $var:
$ eval echo hi `escape "$var"`
hi ; echo gotcha!
$
A less contrived example is passing arguments to Mail Avenger bodytest commands containing possibly unsafe environment variables. For
example, you might write a hypothetical reject_bcc script to reject mail not explicitly addressed to the recipient:
#!/bin/sh
formail -x to -x cc -x resent-to -x resent-cc
| fgrep "$1" > /dev/null
&& exit 0
echo "<$1>.. address does not accept blind carbon copies"
exit 100
To invoke this script, passing it the recipient address as an argument, you would need to put the following in your Mail Avenger rcpt
script:
bodytest reject_bcc `escape "$RECIPIENT"`
SEE ALSO avenger(1),
The Mail Avenger home page: <http://www.mailavenger.org/>.
BUGS
escape is designed for the Bourne shell, which is what Mail Avenger scripts use. escape might or might not work with other shells.
AUTHOR
David Mazieres
Mail Avenger 0.8.3 2012-04-05 escape(1)