Can someone tell me how to boot from a usb flash drive

First you need a computer which is capable of being booted from a usb, check your BIOS options.
There are numerous ways to do it. Since you are posting at a Linux forum, does this mean boot some Linux distribution from a usb?
Do you mean to boot a LiveCD from a flash drive?
Or do you mean install a Linux system to an external usb drive and boot it?

You can use software such as unetbootin to put a LiveCD on a flash drive from a Linux, windows or Mac system. You can use the dd command (numerous posts here explaining it, use the Search function on the right), you can use pendrivelinux aka universal usb installer from windows. Lots of options.

Hi there,

the questions splits in two:
1. How do I make a bootable USB drive?
2. How do I use a bootable USB drive?

There are a few tools that create bootable USB drives from most Linux ISO images. The one that comes first to my mind is UNetbootin. That program is available for Linux as well as Windows, so that you can even create your bootable USB media from within Windows. You just plug your USB pen drive in, run the program (UNetbootin), select an ISO image, and there you go.

Actually booting from a USB pen drive is a different thing. First, not all USB memory devices support this properly, then, not all BIOSes support it. Some claim they do, but once you select the USB drive as the boot device, they just ignore it.

But the most common way is to press a certain function key immediately after the first BIOS messages appear on the screen (often it's F8, F11 or F12, depends on the BIOS). That makes a list of bootable devices pop up on the screen, one of which should be the USB drive. Just select it (typically using arrow keys and Enter), and that's it.

[X] Doc CPU

I have Linux Mint 15 (Olivia) the usb has the Mint 17 ISO.

Mint probably has it's own software to do this but I don't use Mint so can't check. You could go to the unetbootin site below, download unetbootin for Linux and use it to create a bootable iso. Instructions are on the page. Scroll down the page to installation and screenshots. Since you already have the iso downloaded, just open unetbootin and click on the tab with the three dots (...) to navigate to the directory where the Mint iso is and go from there. Make sure the flash drive is plugged in before you open unetbootin.

http://unetbootin.sourceforge.net/

If you loaded the iso correcxtly on usb, it may be listed under hdd's in bios, especially if it's a san disk.

Got it, thanks.

What do you mean exactly? Do mean that if you view the contents of the USB, you see a "linuxmint-17-....iso" file? If so, then you didn't create a bootable USB disk, but you just copied the ISO file onto its file system.

Linux Mint ISO files can be dumped onto a USB device to make the device bootable (I have done that a few times), but that is a very different operation from simply copying the ISO file to the file system.

Most computers since 2006 support booting from USB. It's basically treated like any other storage device. You can forgo some partitioning and bootloader stuff by using dd to copy a live distro iso file to the whole usb device. Although I tend to do an install with debootstrap, or to rsync an existing install or a live images root filesystem onto a partition on the usb drive. Then I use an existing installs bootloader to boot it. And install the bootloader on that device while running on the distro to be booted. Once a distro and bootloader is on the usb device you can change the boot order of your bios / cmos / UEFI / ... whatever applies to boot it first.

Things get a lot less intuitive these days with UEFI. Although x86 devices still let you disable secure boot and enable CSM in most cases. At which point it mostly behaves like any legacy computer. Sort of, as I can't seem to spam the hotkey fast enough in a lot of cases and have to use windows to tell the machine to reboot to the other boot menu on the only UEFI machine in the house. And maybe other quirks with GPT partitioning which is required for storage devices > 2TB in size. And probably required for UEFI booting without disabling secure boot and enabling CSM / legacy mode.

Bear in mind that if you boot the same device and distro across multiple machines you may need to do some fiddling with networking and video drivers when switching between them. And USB flash sticks tend to be horridly slow. To the point that you'll be waiting on file caching, not the network when watching youtube videos. SDHC cards are much faster on the cheap end. But still not comparable to modern SSDs and the likes.

We need to have computer specs and what distro.

Can you post solution as to help others?

Right clicked on device in file directory > select mount & make bootable.

Thanks for the update and solution. Pretty easy.

Thanks Jefro!