diff --git a/benches/bedtools_comparison.rs b/benches/bedtools_comparison.rs
index 0a3cdf2..89e8e91 100644
--- a/benches/bedtools_comparison.rs
+++ b/benches/bedtools_comparison.rs
@@ -8,11 +8,11 @@ use criterion::{criterion_group, criterion_main, Criterion};
 use granges::test_utilities::{granges_binary_path, random_bedfile};
 use std::process::Command;
 
-const BED_LENGTH: usize = 10_000;
+const BED_LENGTH: usize = 100_000;
 
 fn bench_range_adjustment(c: &mut Criterion) {
     // create the benchmark group
-    let mut group = c.benchmark_group("slop vs adjust");
+    let mut group = c.benchmark_group("adjust");
 
     // create the test data
     let input_bedfile = random_bedfile(BED_LENGTH);
@@ -56,7 +56,7 @@ fn bench_range_adjustment(c: &mut Criterion) {
 
 fn bench_filter_adjustment(c: &mut Criterion) {
     // create the benchmark group
-    let mut group = c.benchmark_group("intersect vs filter");
+    let mut group = c.benchmark_group("filter");
 
     // create the test data
     let random_bedfile_left_tempfile = random_bedfile(BED_LENGTH);
@@ -99,5 +99,56 @@ fn bench_filter_adjustment(c: &mut Criterion) {
     });
 }
 
-criterion_group!(benches, bench_filter_adjustment, bench_range_adjustment);
+fn bench_flank(c: &mut Criterion) {
+    // create the benchmark group
+    let mut group = c.benchmark_group("flank");
+
+    // create the test data
+    let random_bedfile_tempfile = random_bedfile(BED_LENGTH);
+    let random_bedfile = random_bedfile_tempfile.path();
+
+    // configure the sample size for the group
+    // group.sample_size(10);
+    group.bench_function("bedtools_flank", |b| {
+        b.iter(|| {
+            let bedtools_output = Command::new("bedtools")
+                .arg("flank")
+                .arg("-g")
+                .arg("tests_data/hg38_seqlens.tsv")
+                .arg("-l")
+                .arg("20")
+                .arg("-r")
+                .arg("30")
+                .arg("-i")
+                .arg(random_bedfile)
+                .output()
+                .expect("bedtools flank failed");
+            assert!(bedtools_output.status.success());
+        });
+    });
+
+    group.bench_function("granges_filter", |b| {
+        b.iter(|| {
+            let granges_output = Command::new(granges_binary_path())
+                .arg("flank")
+                .arg("--genome")
+                .arg("tests_data/hg38_seqlens.tsv")
+                .arg("--left")
+                .arg("20")
+                .arg("--right")
+                .arg("30")
+                .arg(random_bedfile)
+                .output()
+                .expect("granges adjust failed");
+            assert!(granges_output.status.success());
+        });
+    });
+}
+
+criterion_group!(
+    benches,
+    bench_filter_adjustment,
+    bench_range_adjustment,
+    bench_flank,
+);
 criterion_main!(benches);
diff --git a/scripts/benchmark_summary.py b/scripts/benchmark_summary.py
new file mode 100644
index 0000000..110d27b
--- /dev/null
+++ b/scripts/benchmark_summary.py
@@ -0,0 +1,53 @@
+import os
+import json
+
+
+def extract_mean_point_estimate(estimates_path):
+    with open(estimates_path, "r") as file:
+        data = json.load(file)
+    return data["mean"]["point_estimate"]
+
+
+def calculate_ratios(criterion_dir):
+    comparisons = {}  # Store comparison: ratio
+
+    subcommand_benches = [d for d in os.listdir(criterion_dir) if d != "report"]
+
+    for subcommand in subcommand_benches:
+        benches = dict()
+        runs = os.listdir(os.path.join(criterion_dir, subcommand))
+
+        for dir in runs:
+            if dir.startswith("report"):
+                continue
+            if dir.startswith("bedtools"):
+                bedtools_bench = os.path.join(
+                    criterion_dir, subcommand, dir, "new", "estimates.json"
+                )
+                benches["bedtools"] = extract_mean_point_estimate(bedtools_bench)
+            if dir.startswith("granges"):
+                granges_bench = os.path.join(
+                    criterion_dir, subcommand, dir, "new", "estimates.json"
+                )
+                benches["granges"] = extract_mean_point_estimate(granges_bench)
+            comparisons[subcommand] = benches
+
+    # Calculate and print ratios for each comparison
+    for comparison, tools in comparisons.items():
+        if len(tools) == 2:
+            bedtools_time, granges_time = tools.values()
+            # Calculate the ratio and convert it to a percentage
+            percent_faster = ((bedtools_time - granges_time) / bedtools_time) * 100
+            # Format the output to show 3 decimal places
+            print(
+                f"{comparison} - Granges is {percent_faster:.3f}% faster than Bedtools"
+            )
+
+
+def main():
+    criterion_dir = "target/criterion"
+    calculate_ratios(criterion_dir)
+
+
+if __name__ == "__main__":
+    main()
diff --git a/src/commands.rs b/src/commands.rs
index b2601b4..d0cfc01 100644
--- a/src/commands.rs
+++ b/src/commands.rs
@@ -53,7 +53,7 @@ pub fn granges_adjust(
             let possibly_adjusted_range = adjust_range(range, -both, both, length);
 
             if let Some(range_adjusted) = possibly_adjusted_range {
-                writer.write_all(&range_adjusted.to_tsv().into_bytes())?;
+                writeln!(writer, "{}", &range_adjusted.to_tsv())?;
             } else {
                 skipped_ranges += 1;
             }
@@ -259,7 +259,7 @@ pub fn granges_flank(
                             let flanking_ranges = range
                                 .flanking_ranges::<GenomicRangeRecord<String>>(left, right, length);
                             for flanking_range in flanking_ranges {
-                                writer.write_all(&flanking_range.to_tsv().into_bytes())?;
+                                writeln!(writer, "{}", &flanking_range.to_tsv())?;
                             }
                         }
                     } else {
@@ -273,7 +273,7 @@ pub fn granges_flank(
                             let flanking_ranges = range
                                 .flanking_ranges::<GenomicRangeEmptyRecord>(left, right, length);
                             for flanking_range in flanking_ranges {
-                                writer.write_all(&flanking_range.to_tsv().into_bytes())?;
+                                writeln!(writer, "{}", &flanking_range.to_tsv())?;
                             }
                         }
                     }
@@ -290,7 +290,7 @@ pub fn granges_flank(
                             let flanking_ranges = range
                                 .flanking_ranges::<GenomicRangeRecord<String>>(left, right, length);
                             for flanking_range in flanking_ranges {
-                                writer.write_all(&flanking_range.to_tsv().into_bytes())?;
+                                writeln!(writer, "{}", &flanking_range.to_tsv())?;
                             }
                         }
                     } else {
@@ -304,7 +304,7 @@ pub fn granges_flank(
                             let flanking_ranges = range
                                 .flanking_ranges::<GenomicRangeEmptyRecord>(left, right, length);
                             for flanking_range in flanking_ranges {
-                                writer.write_all(&flanking_range.to_tsv().into_bytes())?;
+                                writeln!(writer, "{}", &flanking_range.to_tsv())?;
                             }
                         }
                     }
diff --git a/tests/bedtools_validation.rs b/tests/bedtools_validation.rs
index 3608877..7d204d2 100644
--- a/tests/bedtools_validation.rs
+++ b/tests/bedtools_validation.rs
@@ -76,7 +76,7 @@ fn test_against_bedtools_slop() {
 /// granges filter --genome <genome> --left <left> --right <right>
 #[test]
 fn test_against_bedtools_intersect_wa() {
-    let num_ranges = 100_000;
+    let num_ranges = 1_000_000;
 
     let random_bedfile_left_tempfile = random_bedfile(num_ranges);
     let random_bedfile_right_tempfile = random_bedfile(num_ranges);
@@ -131,15 +131,11 @@ fn test_against_bedtools_intersect_wa() {
 /// granges filter --genome <genome> --left 10 --right 20 <input>
 #[test]
 fn test_against_bedtools_flank() {
-    let num_ranges = 100_000;
+    let num_ranges = 1_000;
 
     let random_bedfile_tempfile = random_bedfile(num_ranges);
     let random_bedfile = random_bedfile_tempfile.path();
 
-    // for testing: uncomment and results are local for inspection
-    // let random_bedfile_left = Path::new("test_left.bed");
-    // let random_bedfile_right = Path::new("test_right.bed");
-
     granges_random_bed(
         "tests_data/hg38_seqlens.tsv",
         num_ranges,
@@ -148,7 +144,6 @@ fn test_against_bedtools_flank() {
     )
     .expect("could not generate random BED file");
 
-    let bedtools_outfile = temp_bedfile();
     let bedtools_output = Command::new("bedtools")
         .arg("flank")
         .arg("-g")
@@ -159,18 +154,9 @@ fn test_against_bedtools_flank() {
         .arg("30")
         .arg("-i")
         .arg(&random_bedfile)
-        .arg(bedtools_outfile.path())
         .output()
         .expect("bedtools flank failed");
 
-    let bedtools_sorted_output = Command::new("bedtools")
-        .arg("sort")
-        .arg("-i")
-        .arg(bedtools_outfile.path())
-        .output()
-        .expect("bedtools intersect failed");
-
-    let granges_outfile = temp_bedfile();
     let granges_output = Command::new(granges_binary_path())
         .arg("flank")
         .arg("--genome")
@@ -180,30 +166,20 @@ fn test_against_bedtools_flank() {
         .arg("--right")
         .arg("30")
         .arg(&random_bedfile)
-        .arg(granges_outfile.path())
         .output()
         .expect("granges flank failed");
 
-    let granges_sorted_output = Command::new("bedtools")
-        .arg("sort")
-        .arg("-i")
-        .arg(bedtools_outfile.path())
-        .output()
-        .expect("bedtools intersect failed");
+    assert!(bedtools_output.status.success(), "{:?}", bedtools_output);
+    assert!(granges_output.status.success(), "{:?}", granges_output);
 
-    assert!(
-        bedtools_sorted_output.status.success(),
-        "{:?}",
-        bedtools_sorted_output
-    );
-    assert!(
-        granges_sorted_output.status.success(),
-        "{:?}",
-        granges_sorted_output
-    );
+    let bedtools_str = String::from_utf8_lossy(&bedtools_output.stdout);
+    let granges_str = String::from_utf8_lossy(&granges_output.stdout);
 
-    assert_eq!(
-        String::from_utf8_lossy(&bedtools_output.stdout),
-        String::from_utf8_lossy(&granges_output.stdout)
-    );
+    let mut bedtools_ranges: Vec<_> = bedtools_str.split("\n").collect();
+    let mut granges_ranges: Vec<_> = granges_str.split("\n").collect();
+
+    bedtools_ranges.sort();
+    granges_ranges.sort();
+
+    assert_eq!(bedtools_ranges, granges_ranges);
 }