add hashit tool for generating and verifying files checksums

1 files changed, 54 insertions, 0 deletions

diff --git a/hashit b/hashit
new file mode 100755
index 0000000..1f08d7e
--- /dev/null
+++ b/hashit
@@ -0,0 +1,54 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+# @describe Generate or verify SHA512 checksums
+# @meta version 1.0.0
+# @meta require-tools sha512sum
+# @meta combine-shorts
+#
+# @flag -s --single-file Use single hash file (default: $HASHIT_SINGLE_FILE_NAME)
+# @flag -c --check Verify checksums
+# @flag -f --force Overwrite existing hash files
+#
+# @arg files+ Files to hash or verify
+#
+# @env HASHIT_SINGLE_FILE_NAME=SHA512SUMS Hash file name for single-file mode
+
+check_file_and_fail() {
+  if [ -f "$1" ] && [ -z "${argc_force:-}" ]; then
+    echo "error: file '$1' exists; use -f to force overwrite" >&2
+    exit 1
+  fi
+}
+
+main() {
+  if [ -n "${argc_single_file:-}" ]; then
+    if [ -n "${argc_check:-}" ]; then
+      sha512sum -c "$HASHIT_SINGLE_FILE_NAME"
+    else
+      check_file_and_fail "$HASHIT_SINGLE_FILE_NAME"
+      sha512sum "${argc_files[@]?}" >"$HASHIT_SINGLE_FILE_NAME"
+    fi
+  else
+    local hash_file
+    if [ -n "${argc_check:-}" ]; then
+      for file in "${argc_files[@]?}"; do
+        if [[ "$file" == *.sha512 ]]; then
+          hash_file="$file"
+        else
+          hash_file="${file}.sha512"
+        fi
+        sha512sum -c "$hash_file"
+      done
+    else
+      for file in "${argc_files[@]?}"; do
+        hash_file="${file}.sha512"
+        check_file_and_fail "$hash_file"
+        echo "$(sha512sum "$file" | cut -d ' ' -f 1)  $(basename "$file")" >"$hash_file"
+      done
+    fi
+  fi
+}
+
+eval "$(argc --argc-eval "$0" "$@")"