Newbie question: modulo operator with negative operand, bug or feature?
Hi,
I'm new to the Ash shell so my apologies if this is well known. In normal maths and other shells and languages I've used, the modulo operator always returns a positive remainder. For example see this discussion (first post so I can't hyperlink it):
I need to find out if a variable contains a certain text string, then do something about it.
Here is what I mean, but I don't know how to get a "contains" operator
# We have volumes called:
# /Volumes/BackupsA_K
# /Volumes/BackupsL_Z
# /Volumes/Backups_Admin
# (could be more, etc)... (5 Replies)
When i tyr this, it gives me a syntax error...i tried removing quotes,removing spaces,replacing -eq with '='.. Can somebody suggest that is the problem?
if ]; then (4 Replies)
Hello everyone,
Just started UNIX today! In our school we use solaris. I just want to know how do I setup Solaris 10 not the GUI one, the one where you have to type the commands like ECHO, ls, pwd, etc... I have windows xp and I also have vmware.
I hope I am not missing anything! :p (4 Replies)
Hello everyone,
I am having to do a lot of perl scripting these days and I am learning a lot.
I have this problem
I want to move files from a folder and all its sub folders to one parent folder, they are all .gz files..
there is folder1\folder2\*.gz
and there are about 50 folders... (1 Reply)
Hi guys,
I confused about syntax used in OR script as follow:
I have this sample file separated by "|" containing:
January|Month No. 1
February|Month No. 2
March|Month No. 3
April|Month No. 4
May|Month No. 5
June|Month No. 6
July|Month No. 7
August|Month No. 8
September|Month No. 9... (11 Replies)
hi
i am writing a progrm to print the even numbers and the code which i am following is as follows
#!/usr/bin/bash
echo "enter a number a"
read a
if
then
echo "the number is even"
else
echo "the number is odd"
fi
~
what is the mistake i am doing ...please tell me (3 Replies)
Does anyone know how this line in bash works?
local gotbase= force= nicelevel corelimit
local pid base= user= nice= bg= pid_file=
local cgroup=
These lines are part of the daemon function inside the "functions" file at /etc/init.d in RH. (3 Replies)
Dear All,
I created a "new public repo" on GitHub (without the code for now but will post the code there as needed if anyone wants to fix a bug)
You can report any forum bugs and report issues in the GitHub "Issues Tab" for this repo here:
https://github.com/unixneo/unix.com.bugtracker
... (0 Replies)
Discussion started by: Neo
0 Replies
LEARN ABOUT FREEBSD
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)