April 19, 2019

New HOWTO: The Linux Kernel HOWTO - page 12

Table of Contents

  • April 2, 2001
  11.  Tips and tricks

  11.1.  Redirecting output of the make or patch commands

  If you would like logs of what those `make' or `patch' commands did,
  you can redirect output to a file. First, find out what shell you're
  running: `grep root /etc/passwd' and look for something like

  If you use sh or bash,

      (command) 2>&1 | tee (output file)

  will place a copy of (command)'s output in the file `(output file)'.

  For csh or tcsh, use

      (command) |& tee (output file)

  For rc (Note: you probably do not use rc) it's

      (command) >[2=1] | tee (output file)

  11.2.  Conditional kernel install

  Other than using floppy disks, there are several methods of testing
  out a new kernel without touching the old one. Unlike many other Unix
  flavors, LILO has the ability to boot a kernel from anywhere on the
  disk (if you have a large (500 MB or above) disk, please read over the
  LILO documentation on how this may cause problems). So, if you add
  something similar to

      image = /usr/src/linux/arch/i386/boot/bzImage
          label = new_kernel

  to the end of your LILO configuration file, you can choose to run a
  newly compiled kernel without touching your old /vmlinuz (after run�
  ning lilo, of course). The easiest way to tell LILO to boot a new ker�
  nel is to press the shift key at bootup time (when it says LILO on the
  screen, and nothing else), which gives you a prompt.  At this point,
  you can enter `new_kernel' to boot the new kernel.

  If you wish to keep several different kernel source trees on your
  system at the same time (this can take up a lot of disk space; be
  careful), the most common way is to name them /usr/src/linux-x.y.z,
  where x.y.z is the kernel version. You can then ``select'' a source
  tree with a symbolic link; for example, `ln -sf linux-1.2.2
  /usr/src/linux' would make the 1.2.2 tree current. Before creating a
  symbolic link like this, make certain that the last argument to ln is
  not a real directory (old symbolic links are fine); the result will
  not be what you expect.

  11.3.  Kernel updates

  Russell Nelson (nelson@crynwr.com) summarizes the changes in new
  kernel releases. These are short, and you might like to look at them
  before an upgrade. They are available with anonymous ftp from
  ftp.emlist.com in pub/kchanges or through the URL


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