Top new questions this week:

What does the letter 'u' mean in /dev/urandom?

I understand that reads to /dev/random may block, while reading /dev/urandom is guaranteed not to block. Where does the letter u come into this? What does it signify? Userspace? Unblocking? Micro? ...

/ linux / devices / history / random

asked by Tom Hale 69 votes answered by Tom Hale 73 votes

What's the fastest way to generate a 1 GB text file containing random digits?

I tried a bash script, but it took too long to create a simple 1 MB file. I think the answer lies in using /dev/random or /dev/urandom, but other posts here only show how to add all kinds of data to a ...

/ files / random

asked by posixKing 37 votes answered by Stéphane Chazelas 69 votes

Why doesn't find . -delete delete current directory?

I would expect find . -delete to delete the current directory, but it doesn't. Why not?

/ find / directory / rm

asked by mbroshi 16 votes answered by 林果皞 22 votes

How do I reliably find the full path of a program on the PATH?

I need to find the path of a given program on the PATH using a shell script. The path must be the actual full path of the program, which can be passed later to one of the exec* functions, which does ...

/ shell / path

asked by Sebastian Schrader 8 votes answered by Zachary Brady 8 votes

Is it bad to port forward port 443 for ssh?

I am a student and I keep most of my files on my home computer. Unfortunately, i can't use ssh or scp from my laptop which I use at school because of the firewall. I was thinking about trying to use ...

/ ssh / firewall / port-forwarding

asked by yasgur99 6 votes answered by Elliott Frisch 11 votes

Meaning of '2> >(command)' Redirection in Bash

A while ago I made a script and I added some logging around it, but I forgot how the redirection for the logging works :-( The gist of it is: #!/bin/bash LOGFILE=/some/path/mylogfile ( # here go ...

/ bash / shell-script / io-redirection

asked by NZD 6 votes answered by Eric Renouf 11 votes

Is accepting RELATED,ESTABLISHED for all sources in iptables considered "too open"?

I've often seen the rule -A INPUT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT applied. Whilst I'm not an expert, that particular line concerns me. It's pretty obvious that the rule allows all ...

/ security / iptables / ip / tcp

asked by Dencker 5 votes answered by BillThor 4 votes

Greatest hits from previous weeks:

What do the fields in ls -al output mean?

The ls -al command shows the following output; -rwxrw-r-- 10 root root 2048 Jan 13 07:11 afile.exe What are all the fields in the preceding display?

/ ls

asked by Mr. White 75 votes answered by Flyk 83 votes

Connecting to wifi network through command line

I am trying to connect to my WEP network just using the command-line (Linux). I run: sudo iwconfig wlan0 mode Managed essid 'my_network' key 'xx:xx:... hex key, 26 digits' Then I try to obtain an ...

/ command-line / networking / wifi

asked by Jayson Condor 35 votes answered by Danijel-James W 44 votes

Can you answer these?

Difference between syscalls and raw_syscalls events?

AFAIK different linux tracing tools gather information from /sys/kernel/debug/tracing/events directory where different events are logged. Can anyone explain the difference between "syscalls" event and ...

/ linux / linux-kernel / system-calls

asked by cout_display_name 3 votes

How to list QNAP virtual machines from an SSH command line?

This is partly a straight question and partly an attempt to gain more understanding about how QNAP network servers work. My office uses a local network drive installed with (according to ...

/ ubuntu / networking / windows / samba / smb

asked by Boxbot 2 votes

Interfacing BlueZ without HCI?

Background I'm trying to get a BlueZ based userspace app running on a embedded Linux board to use nRF52832 as a Bluetooth connectivity chip. Seems like nRF52832 doesn't support the HCI interface. ...

/ linux-kernel / bluetooth / bluez

asked by Alan 2 votes