1.20 Preventing Query Output from Scrolling off the Screen
1.20.1 Problem
Query output zooms off the top of your
screen before you can see it.
1.20.2 Solution
Tell mysql to display output a page at a time, or
run mysql in a window that allows scrollback.
1.20.3 Discussion
If a query produces many lines of output, normally they just scroll
right off the top of the screen. To prevent this, tell
mysql to present output a page at a time by
specifying the
--pager option.
--pager=program
tells mysql to use a specific program as your
pager:
% mysql --pager=/usr/bin/less
--pager by itself tells
mysql to use your default pager, as specified in
your
PAGER
environment variable:
% mysql --pager
If your PAGER variable isn't set,
you must either define it or use the first form of the command to
specify a pager program explicitly. To define
PAGER, use the instructions in Recipe 1.9 for setting environment variables.
Within a mysql session, you can turn paging on and
off using \P and
\n. \P
without an argument enables paging using the program specified in
your PAGER variable. \P with an
argument enables paging using the argument as the name of the paging
program:
mysql> \P
PAGER set to /bin/more
mysql> \P /usr/bin/less
PAGER set to /usr/bin/less
mysql> \n
PAGER set to stdout
Output paging was introduced in MySQL 3.23.28.
Another way to deal with long result sets is to use a terminal
program that allows you to scroll back through previous output.
Programs such as xterm for the X Window System,
Terminal for Mac OS X, MacSSH or BetterTelnet for Mac OS, or Telnet
for Windows allow you to set the number of output lines saved in the
scrollback buffer. Under Windows NT, 2000, or XP, you can set up a
DOS window that allows scrollback using the following procedure:
Open the Control Panel. Create a shortcut to the MS-DOS prompt by right clicking on the
Console item and dragging the mouse to where you want to place the
shortcut (on the desktop, for example).
Right click on the shortcut and select the Properties item from the
menu that appears.
Select the Layout tab in the resulting Properties window. Set the screen buffer height to the number of lines you want to save
and click the OK button.
Now you should be able to launch the shortcut to get a scrollable DOS
window that allows output produced by commands in that window to be
retrieved by using the scrollbar.
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