Fixing Terminal Row & Columns Display on Docker and Linux

Ever faced garbled screen on a terminal, text wrapping over and screen command string messed up!
It happens because the terminal is using default row and column value (e.g. columns = 80).

The following command fixes it (tested on Docker container’s terminal)

docker exec -e COLUMNS="`tput cols`" -e LINES="`tput lines`" -ti 

How it Works?

• tput initializes or reset a terminal by providing terminal info to the shell.
• From man page of tput:

  The tput utility uses the terminfo database to make the
  values of terminal-dependent capabilities and information available to the shell
  

• Let’s find the type of terminal

  # echo $TERM
    xterm
  

• Let’s see what’s suggested rows and columns for this terminal.

  # tput cols
  167
  # tput lines
  49
  

• While accessing the container terminal, we passed the number of columns and rows to COLUMNS & LINES variable.
• The terminal database is present at /usr/share/terminfo.

References

• https://linux.die.net/man/1/tput
• https://askubuntu.com/questions/219547/how-do-i-get-more-than-80-columns-in-command-line-mode

Written with StackEdit.