cli: add cut and rev, update tac

1 files changed, 41 insertions, 0 deletions

diff --git a/src/cli/cut.md b/src/cli/cut.md
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+# cut(1)
+
+```sh
+# Remove sections from each line of files(s).
+cut OPT FILE [FILE]
+    -d DELIM     delimiter to tokenize
+    -f LIST      field selector
+    -c LIST      character selector
+```
+
+## Example: only selected characters
+
+```sh
+echo 'aa bb cc dd' | cut -c "1-4"
+# aa b
+
+# Inverted selection.
+echo 'aa bb cc dd' | cut --complement -c "1-4"
+# b cc dd
+```
+
+## Example: only selected fields
+Fields in `cut` are indexed starting from `1` rather than `0`.
+```sh
+# Fields 2 until 3.
+echo 'aa bb cc dd' | cut -d ' ' -f 2-3
+# bb cc
+
+# First field until the 2nd.
+echo 'aa bb cc dd' | cut -d ' ' -f -2
+# aa bb
+
+# Third field until the end.
+echo 'aa bb cc dd' | cut -d ' ' -f 3-
+# cc dd
+
+# If the number of tokens in a line is unkown but we want to remove the last 2
+# tokens we can use rev(1).
+echo 'aa bb cc dd' | rev | cut -d ' ' -f3- | rev
+# aa bb
+```