Hi Andreas,
Sure, the variables explicitly assigned to get exported, that is the
expected behavior.
But there is nothing which explains why the variable COLUMNS becomes an
environment variable.
OK. The description of COLUMNS says:
COLUMNS
Used by the select compound command to determine the terminal
width when printing selection lists. Automatically set if the
checkwinsize option is enabled or in an interactive shell upon
receipt of a SIGWINCH.
Run “ps ax” twice and the results of the second execution is different
from the first if and only if “set -a” was called fiirst. This is NOT an
expected behavior.
You have checkwinsize set. The description of checkwinsize reads:
checkwinsize
If set, bash checks the window size after each external
(non-builtin) command and, if necessary, updates the
values of LINES and COLUMNS. This option is enabled by
default.
So the first invocation of ps, since it's a non-builtin command, makes
bash query the terminal and adjust LINES and COLUMNS.
Do the following and you won’t get a problem: set -a var1=xx var2=xx set +a
All builtin commands.
All is fine, but do the following and COLUMNS gets exported:
set -a
echo $PATH | grep xxx/scripts || PATH=${PATH}:/newdir
ps ax is now truncated, definitely NOT expected
The value of COLUMNS gets modified, and auto-exported since you have
`set -a' enabled.
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU c...@case.edu http://tiswww.cwru.edu/~chet/
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