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Source  : 7235863
Branch  : main
Author  : Kate Taylor <156236911+TaylorKT@users.noreply.github.com>
Time    : 2025-05-30 17:54:34 +0000
Message : Merge pull request #365 from datacarpentry/clarification/grep_example

feat: add a short example of using grep on a non-N string and showing `grep -c`

Author: actions-user

04-redirection.md

@@ -50,6 +50,19 @@ directory:
 $ cd ~/shell_data/untrimmed_fastq
 ```
 
+Let's look for lines that contain `ACGT`.
+
+```bash
+$ grep ACGT SRR098026.fastq
+```
+
+To get only the number of lines with `ACGT`, we can use the `-c` flag.
+This is useful if you are unsure about the number of lines that will be found.
+
+```bash
+$ grep -c ACGT SRR098026.fastq
+```
+
 Suppose we want to see how many reads in our file have really bad segments containing 10 consecutive unknown nucleotides (Ns).
 
 :::::::::::::::::::::::::::::::::::::::::  callout

md5sum.txt

@@ -6,7 +6,7 @@
 "episodes/01-introduction.md" "c0f3f85bf71bfaf19c2b3507d0207378" "site/built/01-introduction.md" "2023-08-15"
 "episodes/02-the-filesystem.md" "70b53ce6f53a88f931e492d876c60fa1" "site/built/02-the-filesystem.md" "2023-05-08"
 "episodes/03-working-with-files.md" "2c331035e2e8cea65fc0386b2e59b303" "site/built/03-working-with-files.md" "2025-05-30"
-"episodes/04-redirection.md" "3f71f2fad3303b1be957191c95bae2f7" "site/built/04-redirection.md" "2024-03-14"
+"episodes/04-redirection.md" "7af92ffeb1bfdc69057917967d8a51ad" "site/built/04-redirection.md" "2025-05-30"
 "episodes/05-writing-scripts.md" "648b54fd474490d69a6177a239be29d3" "site/built/05-writing-scripts.md" "2024-04-17"
 "episodes/06-organization.md" "6a657fb25cd386f2088145a440f2acc3" "site/built/06-organization.md" "2023-05-08"
 "instructors/Extra_lesson.md" "e60e20421674d8dc399eefce404e27f9" "site/built/Extra_lesson.md" "2023-05-08"