many fixes

Docker/docker_compose.txt

@@ -38,6 +38,16 @@ Bash completion (https://docs.docker.com/compose/completion/)::
 					    --rmi all		# + del all service images
 
 
+
+::
+
+    version: '2.1'
+    services:
+      nginx1:
+        env_file: .env
+
+
+
 Example nginx ``docker-compose.yml``::
 
     version: '2'

bash.txt

@@ -3,6 +3,15 @@ BASH
 ====
 
 
+Boolean in BASH::
+
+    VAR=true
+
+    if [ "$VAR" = true ] ; then
+        echo 'true'
+    fi
+
+
 Check if a variable is set::
 
     if [ -z ${var+x} ]; then
@@ -11,6 +20,8 @@ Check if a variable is set::
         echo "var is set to '$var'"
     fi
 
+    # this will return true if a variable is unset or set to the empty string ("")
+    if [ -z "$VAR" ];    
 
 
 

git.txt

@@ -14,6 +14,12 @@ https://git-scm.com/book/ru/v2
 	add <name> 
 
 
+
+Change url::
+
+    git remote set-url origin git@bitbucket.org:johnsmith/test.git
+
+
 ::
 
     git remote add origin https://github.com/johnsmith/test.git
@@ -33,8 +39,9 @@ https://git-scm.com/book/ru/v2
 		       -d hotfix    # delete unused branch
 		       -D testing   # delete unused branch also if not merged
 
-    git checkout testing    # switching to branch testing (HEAD transfer to branch testing)
-			     -b iss53   # create and switching branch
+    git checkout testing        # switching to branch testing (HEAD transfer to branch testing)
+			     -b iss53       # create and switching branch
+    git checkout path/to/file   # switching file version from server
 
     git merge hotfix        # merge current branch with hotfix
 

nginx.txt

@@ -25,9 +25,12 @@ NGINX config
 ::
 
     server {
-        ...
-        client_max_body_size 32m; // размер загружаемого файла клиентом на сервер
-        ...
+        # size of upload files
+        client_max_body_size 32m;
+
+        # 301 redirect
+        return 301 https://example.com$request_uri;
+        return 301 https://$host$request_uri;
     }
 
 

scripts.txt

@@ -0,0 +1,21 @@
+==============
+Useful scripts
+==============
+
+Low disk space alert
+--------------------
+
+::
+
+    #!/bin/bash
+    CURRENT=$(df /data | grep / | awk '{ print $5}' | sed 's/%//g')
+    THRESHOLD=90
+
+    echo "$CURRENT"
+
+    if [ "$CURRENT" -gt "$THRESHOLD" ] ; then
+        echo "Low Disk Space Alert: ${CURRENT}% used"
+      mail -s 'Disk Space Alert' admin@gmail.com << EOF
+    Backup server remaining free space is critically low. Used: $CURRENT%
+    EOF
+    fi

sendmail.txt

@@ -0,0 +1,7 @@
+========
+Sendmail
+========
+
+Send mail from console::
+
+    (echo "Subject:Hi"; echo "Body contents";) | sendmail -v -F "test"  my@mail