In shell script, we ofter need to compare version strings to carry out different actions for different versions. one of the solution would be use bc or test:
echo "2.0 < 3.0" | bc
but sometimes version string will not be pure number, it could be:
2.0-alpha 2.0-beta 2.9a 3.0.1 3.0.1-rc1
on stackoverflow, there comes a better solution. the original post is:https://stackoverflow.com/questions/16989598/bash-comparing-version-numbers/24067243 it use sort -V or gawk to get a better compare. these two solutions both has pro and cons. based on the sort -V solution, I refined my tmux.conf, since the tmux version comes to 2.9a.
run-shell "tmux setenv -g TMUX_VERSION $(tmux -V | cut -c 6-)"
run-shell 'tmux setenv -g TMUX_VERSION_GE_2_1 $(test "$(printf "%s\n" $TMUX_VERSION 2.1|sort -V|head -n 1)" != "2.1";echo $?)'
run-shell 'tmux setenv -g TMUX_VERSION_GE_2_2 $(test "$(printf "%s\n" $TMUX_VERSION 2.2|sort -V|head -n 1)" != "2.2";echo $?)'
run-shell 'tmux setenv -g TMUX_VERSION_GE_2_4 $(test "$(printf "%s\n" $TMUX_VERSION 2.4|sort -V|head -n 1)" != "2.4";echo $?)'
run-shell 'tmux setenv -g TMUX_VERSION_GE_3_0 $(test "$(printf "%s\n" $TMUX_VERSION 3.0|sort -V|head -n 1)" != "3.0";echo $?)'