This looks almost like homework so I'm not gonna go into much details. If you have any specific questions post them back here.
1. Expand the variable "DEBUG" *if, and only if* it's already defined, else use zero.
2. Print the contents of the first script argument.
3. Defines a function that checks if a file does not exist. "tee" is a specific purpose command; Take a look at the man page (man tee).
4. Defines another function that checks if the contents of $DEBUG aren't equal to 1 (numeric value, not string).
5. String assignment.
6. "-z" is a comparison operator used to tell if string has zero length.
In all cases the syntax ${var} is used to "protect" the variables. E.g:
One of the above "echo" statements will work fine and the other will throw an error. Try it for yourself to find out which one fails and why.
Hi all....
I was wondering if there is a lot of differences between /bash and ksh programming.
Im learning about bash programming, but all what I had read in this forum, points me to learn more about ksh over bash. Is that right and why?
Unfortunately, I can’t write ksh progs on my work,... (2 Replies)
how to i grep a keyword which ignore upper case or lower case.
for an example :
user enter CoUcH
and the grep also can grep couch which in text.txt although upper or loever case is different .. how to do that ?
any idea? (1 Reply)
I have a file that is 20 - 80+ MB in size that is a certain type of log file.
It logs one of our processes and this process is multi-threaded. Therefore the log file is kind of a mess. Here's an example:
The logfile looks like: "DATE TIME - THREAD ID - Details", and a new file is created... (4 Replies)
Doubt #1
I have a program that I want the user to input date. When the user inputs the date, is it able to format it to system date dd-mm-yyy and then echo the value into a text file?
Doubt#2
If the above is not going to work, I tried to have the system date appear in the user input field and... (6 Replies)
Write a Shell script to analyse the disk usage of students in a particular class.
The program should allow the user running the script to input the particular class name (group name) as an argument to the script.
The script should create a file called “logfile” in the home directory of the user... (2 Replies)
Hello
I have a unique problem of needing to delete large files slowly off of an XSan.
I was wondering if there is a script I could use to delete 100gb chunks of files and folders that get placed in to a watch folder, slowly so as not to disrupt the other users. I would like to use Automator in... (0 Replies)
Hello all;
I have little knowledge of bash programming, and I was wondering if you could help me out.
I would like to create a bash script, as detailed below.
process.sh is the bash script itself
list.dl is a text file. In this text file, the first line is the directory from... (1 Reply)
Please take a look I am stuck on step 4
1. The problem statement, all variables and given/known data:
#!/bin/bash
### ULI101 - ASSIGNMENT #2 (PART A) - DUE DATE Wed, Aug 3, 2011, before 12 midnight.
###====================================================================================
###... (13 Replies)
Hi! I'm new in bash programming and I need to make an script that reads a txt file line by line (every line is like "Name;FirstLastName;SecondLastName;Sex") and has to give every student 3 random marks, its average and add a counter if they are male/female and if they passed. I've been trying with... (4 Replies)
Discussion started by: HeartHacker
4 Replies
LEARN ABOUT POSIX
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)