diff options
Diffstat (limited to 'bin/rndl.awk')
-rw-r--r-- | bin/rndl.awk | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/bin/rndl.awk b/bin/rndl.awk new file mode 100644 index 00000000..8359af90 --- /dev/null +++ b/bin/rndl.awk @@ -0,0 +1,29 @@ +# Print a random line from input + +# Process arguments +BEGIN { + + # Name self + self = "rndl" + + # Seed the random number generator + "rnds 2>/dev/null" | getline seed + srand(seed) +} + +# Iterate over the lines, randomly assigning the first field of each one with a +# decreasing probability +rand() * NR < 1 { ln = $0 } + +# Check and print +END { + + # Check that we processed at least one line + if (!NR) { + printf "%s: No lines found on input\n", self | "cat >&2" + exit(1) + } + + # Print the line + print ln +} |