How to test strings for lexicographic less than or equal in Bash?

You can flip the comparison and sign around and test negatively:

$ a="abc"
$ b="abc"
$ if ! [[ "$b" > "$a" ]] ; then  echo "a <= b" ; fi
a <= b

If you want collating sequence of "A" then "a" then "B"... use:

shopt -s nocaseglob

You need to use || with an additional condition instead of <=:

[[ "$a" < "$b" || "$a" == "$b" ]]

Just negate the greater than test:

if [[ ! "a" > "b" ]]

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