$RANDOM  –  Random Integer

$RANDOM expands to a random integer in the range [0, 32767]. Assigning a values seeds the random name generator.

The random generator generates the same numbers in subshells unless you seed it.

Links

• Z Shell manual

Examples

Seed random generator and print random value

1 2 3 4 5 6 7 8 9 10 11

# without seeding, the same numbers are generated in subshells echo "subshell 1: $(echo $RANDOM)" echo "subshell 2: $(echo $RANDOM)" # seed with "seconds since epoch" followed by "nanoseconds" to enforce different values RANDOM=$(date +%s%N) echo "after seeding: subshell 1: $(echo $RANDOM)" sleep .1 RANDOM=$(date +%s%N) echo "after seeding: subshell 2: $(echo $RANDOM)"

Output:

1 2 3 4

subshell 1: 26215 subshell 2: 26215 after seeding: subshell 1: 23977 after seeding: subshell 2: 1130