How do I increase the scrollback buffer in a running screen session

Question

Lets say I have a currently running screen session I am interacting with through putty   I ve realized that the scrollback buffer is too small and would like to increase it without starting a new screen session   Is there a way to do this

User · Answer

There is a minimal amount of  default  buffer when you startup a  screen  session within your  putty session   I use screens a lot in my work  so I can tell you that you will not have a combination of  screen  buffer  amp   putty  buffer within your  screen  session     Setting the default number of scrollback lines by adding defscrollback 10000 to your    screenrc file is the correct solution     By the way  I use  defscrollback 200000  in my   screenrc file

User · Answer

WARNING  setting this value too high may cause your system to experience a significant hiccup   The higher the value you set  the more virtual memory is allocated to the screen process when initiating the screen session   I set my    screenrc to  defscrollback 123456789  and when I initiated a screen  my entire system froze up for a good 10 minutes before coming back to the point that I was able to kill the screen process  which was consuming 16 6GB of VIRT mem by then

User · Answer

Press Ctrl-a then   and then type  scrollback 10000   to get a 10000 line buffer  for example   You can also set the default number of scrollback lines by adding  defscrollback 10000   to your    screenrc file   To scroll  if your terminal doesn t allow you to by default   press Ctrl-a ESC and then scroll  with the usual Ctrl-f for next page or Ctrl-a for previous page  or just with your mouse wheel   two-fingers   To exit the scrolling mode  just press ESC   Another tip  Ctrl-a i shows your current buffer setting

User · Answer

For posterity  this answer is incorrect as noted by Steven Lu  Leaving original text however   Original answer   To those arriving via web search  several years later      When using screen  your scrollback buffer is a combination of both the screen scrollback buffer as the two previous answers have noted  as well as your putty scrollback buffer   Be sure that you are increasing BOTH the putty scrollback buffer as well as the screen scrollback buffer  else your putty window itself won t let you scroll back to see your screen s scrollback history  overcome by scrolling within screen with ctrl a- gt ctrl u   You can change your putty scrollback limit under the  Window  category in the settings  Exiting and reopening a putty session to your screen won t close your screen  assuming you just close the putty window and don t type exit   as the OP asked for   Hope that helps identify why increasing the screen s scrollback buffer doesn t solve someone s problem

User · Answer

The man page explains that you can enter command line mode in a running session by typing Ctrl A     then issuing the scrollback  lt num gt  command

User · Answer

As Already mentioned we have two ways    Per screen  session  interactive setting And it s done interactively  And take effect immediately  CTRL   A followed by   And we type scrollback 1000000 And hit ENTER You detach from the screen and come back  It will be always the same  You open another new screen  And the value is reset again to default  So it s not a global setting    And the permanent default setting Which is done by adding defscrollback 1000000 to  screenrc  in home  defscrollback and not scrollback  def stand for default  What you need to know is if the file is not created   You create it    gt  cd    amp  amp  vim  screenrc  And you add defscrollback 1000000 to it  Or in one command  gt  echo  quot defscrollback 1000000 quot   gt  gt   screenrc   if not created already  Taking effect When you add the default to  screenrc  The already running screen at re-attach will not take effect  The  screenrc run at the screen creation  And it make sense  Just as with a normal console and shell launch  And all the new created screens will have the set value  Checking the screen effective buffer size To check type CTRL   A followed by i And The result will be as  Importantly the buffer size is the number after the   sign  in the illustration i set it to 1 000 000  Note too that when you change it interactively  The effect is immediate and take over the default value  Scrolling CTRL  A followed by ESC  to enter the copy mode   Then navigate with Up Down or PgUp PgDown And ESC again to quit that mode   Extra info  to copy hit ENTER to start selecting  Then ENTER again to copy  Simple and cool  Now the buffer is bigger   And that s sum it up for the important details

[linux] How do I increase the scrollback buffer in a running screen session?

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