diff --git a/doc/cron.md b/doc/cron.md
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--- a/doc/cron.md
+++ /dev/null
@@ -1,8 +0,0 @@
-### Cron
-
-```crontab -e```
-
-```0 0 1 1 * script.sh``` - Every year in 1 January 00:00:00 \
-```*/1 * * * * script.sh``` - Every minute\
-```0 */3 * * 2,5 script.sh``` - One time per 3 hours in Tue and Fri\
-```0 0,12 1 */2 * script.sh``` - At minute 0 past hour 0 and 12 on day-of-month 1 in every 2nd month
diff --git a/doc/gpg.md b/doc/gpg.md
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--- a/doc/gpg.md
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-## GPG
-
-### Encrypt
-1. ```gpg --full-generate-key```
-2. ```gpg --export -a "thek4n" > public.key``` -a ASCII
-3. ```gpg --fingerprint "thek4n"``` (send fingerprint IRL)
-4. ```gpg -seaR "john" -u "thek4n" file``` -s sign, -e asymmetric, -a ASCII, -R ciphered receiver, -u secret key
-
-### Decrypt
-1. ```gpg --import public.key```
-2. ```gpg --fingerprint "thek4n"``` (check fingerprint)
-3. ```gpg -d --try-secret-key "john" file.asc > res.txt```
-
-### Sign message (one file)
-enc: ```gpg -u "thek4n" --clear-sign -s file``` -u secret key, --clear-sign ascii\
-dec: ```gpg -d file.asc```
-
-### Sign binary (file and sign)
-enc: ```gpg -u "thek4n" -b file``` -b detached sign\
-dec: ```gpg --verify file.sig file```
diff --git a/doc/ssh.md b/doc/ssh.md
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--- a/doc/ssh.md
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-`/etc/ssh/sshd_config`
-     
-
-* Access for VPS:
-     * ```
-       PubkeyAuthentication yes
-       PasswordAuthentication no  # only ssh-key
-       
-       Match User root
-           PasswordAuthentication yes
-       ```
-
-* For local server:
-    * ```
-      PermitRootLogin no  # only sudo and su
-      PubkeyAuthentication yes
-      PasswordAuthentication no  # only ssh-key
-
-      Match Host 192.168.50.*,127.0.0.1
-          PermitRootLogin yes  # root only local
-          Match User root
-              PasswordAuthentication yes  # root auth only password from local   
-      ```
-
-https://www.opennet.ru/base/sec/ssh_tips.txt.html