LINES and COLUMNS environmental variables lost in a script

user_25891 0
Viewed 51495

Consider the following:

me@mine:~$ cat a.sh 
#!/bin/bash
echo "Lines: " $LINES
echo "Columns: " $COLUMNS
me@mine:~$ ./a.sh 
Lines: 
Columns: 
me@mine:~$ echo "Lines: " $LINES
Lines:  52
me@mine:~$ echo "Columns: " $COLUMNS
Columns:  157
me@mine:~$

The variables $LINES and $COLUMNS are shell variables, not environmental variables, and thus are not exported to the child process (but they are automatically updated when I resize the xterm window, even when logged in via ssh from a remote location). Is there a way in which I can let my script know the current terminal size?

EDIT: I need this as a workaround do this problem: vi (as well as vim, less, and similar commands) messes up the screen every time I use it. Changing the terminal is not an option, and thus I'm looking for workarounds (scrolling down $LINES lines surely is not the perfect solution, but at least is better than losing the previous screen)

environment-variables shell terminal bash
11 Answers

My experince that you should start the script by the '. script_to_run' form, instead of the 'scritp_to_run'. A simple check as follows:

'(( ${#COLUMNS} )) || { echo "Try start like '. name'" ; return 1 ; }
user_44894150
Related