Newbie here. My goal is to have the expect script log into the Ubuntu 18.04 server and run two commands (lsb_release -a and ip addr) and eventually pipe the output/results to a file. For now, I would be happy to get this one command or two to run successfully. How to fix this?
#!/usr/bin/expect ... (3 Replies)
I am using the below to random generate a password but I need to have 2 numeric characters and 6 alphabetic chars
head /dev/urandom | tr -dc A-Za-z0-9 | head -c 8 ; echo ''
6USUvqRB
------ Post updated at 04:43 PM ------
Any Help folks - Can the output be passed onto a sed command to... (9 Replies)
Hello,
I have created a script to generate a random password on Linux/Solaris, but I simply cannot use it on my AIX VMs since Bash isn't installed on them.
I need a password that is randomly created with the following... (12 Replies)
Need to use dd to generate a large file from a sample file of random data. This is because I don't have /dev/urandom.
I create a named pipe then:
dd if=mynamed.fifo do=myfile.fifo bs=1024 count=1024
but when I cat a file to the fifo that's 1024 random bytes:
cat randomfile.txt >... (7 Replies)
Hi,,
Here i have attached a text file where iam facing problem in my code.
Please read the file and help me out of this issue..
Thanks in advance (4 Replies)
I need a function to generate a random alphanumeric password in C code. It needs to be between 6-8 characters and follow the following rules:
Reject if same char appears # time: 4 or more
Reject if same char appears consecutively: 3 or more
I have the following random password working for... (2 Replies)
Hello All...
Can someone help me generate a random password which will be 7 characters long which contains alpha-numeric characters using shell script.
I am looking to store the output of the script that generates the password to a variable within a script and use it as the password.
... (5 Replies)
RANDOM(4) Linux Programmer's Manual RANDOM(4)NAME
random, urandom - kernel random number source devices
DESCRIPTION
The character special files /dev/random and /dev/urandom (present since Linux 1.3.30) provide an interface to the kernel's random number
generator. File /dev/random has major device number 1 and minor device number 8. File /dev/urandom has major device number 1 and minor
device number 9.
The random number generator gathers environmental noise from device drivers and other sources into an entropy pool. The generator also
keeps an estimate of the number of bit of the noise in the entropy pool. From this entropy pool random numbers are created.
When read, the /dev/random device will only return random bytes within the estimated number of bits of noise in the entropy pool.
/dev/random should be suitable for uses that need very high quality randomness such as one-time pad or key generation. When the entropy
pool is empty, reads to /dev/random will block until additional environmental noise is gathered.
When read, /dev/urandom device will return as many bytes as are requested. As a result, if there is not sufficient entropy in the entropy
pool, the returned values are theoretically vulnerable to a cryptographic attack on the algorithms used by the driver. Knowledge of how to
do this is not available in the current non-classified literature, but it is theoretically possible that such an attack may exist. If this
is a concern in your application, use /dev/random instead.
CONFIGURING
If your system does not have /dev/random and /dev/urandom created already, they can be created with the following commands:
mknod -m 644 /dev/random c 1 8
mknod -m 644 /dev/urandom c 1 9
chown root:root /dev/random /dev/urandom
When a Linux system starts up without much operator interaction, the entropy pool may be in a fairly predictable state. This reduces the
actual amount of noise in the entropy pool below the estimate. In order to counteract this effect, it helps to carry entropy pool informa-
tion across shut-downs and start-ups. To do this, add the following lines to an appropriate script which is run during the Linux system
start-up sequence:
echo "Initializing kernel random number generator..."
# Initialize kernel random number generator with random seed
# from last shut-down (or start-up) to this start-up. Load and
# then save 512 bytes, which is the size of the entropy pool.
if [ -f /var/random-seed ]; then
cat /var/random-seed >/dev/urandom
fi
dd if=/dev/urandom of=/var/random-seed count=1
Also, add the following lines in an appropriate script which is run during the Linux system shutdown:
# Carry a random seed from shut-down to start-up for the random
# number generator. Save 512 bytes, which is the size of the
# random number generator's entropy pool.
echo "Saving random seed..."
dd if=/dev/urandom of=/var/random-seed count=1
FILES
/dev/random
/dev/urandom
AUTHOR
The kernel's random number generator was written by Theodore Ts'o (tytso@athena.mit.edu).
SEE ALSO
mknod (1)
RFC 1750, "Randomness Recommendations for Security"
Linux 1997-08-01 RANDOM(4)