1 files changed, 21 insertions, 3 deletions
diff --git a/bash.html.markdown b/bash.html.markdown
index 191f916a..f3c9cccc 100644
--- a/bash.html.markdown
+++ b/bash.html.markdown
@@ -83,24 +83,33 @@ echo Hello, $Name!
 
 # We have the usual if structure:
 # use 'man test' for more info about conditionals
-if [ $Name -ne $USER ]
+if [ $Name != $USER ]
 then
     echo "Your name isn't your username"
 else
     echo "Your name is your username"
 fi
 
+# NOTE: if $Name is empty, bash sees the above condition as:
+if [ != $USER ]
+# which is invalid syntax
+# so the "safe" way to use potentially empty variables in bash is:
+if [ "$Name" != $USER ] ...
+# which, when $Name is empty, is seen by bash as:
+if [ "" != $USER ] ...
+# which works as expected
+
 # There is also conditional execution
 echo "Always executed" || echo "Only executed if first command fails"
 echo "Always executed" && echo "Only executed if first command does NOT fail"
 
 # To use && and || with if statements, you need multiple pairs of square brackets:
-if [ $Name == "Steve" ] && [ $Age -eq 15 ]
+if [ "$Name" == "Steve" ] && [ "$Age" -eq 15 ]
 then
     echo "This will run if $Name is Steve AND $Age is 15."
 fi
 
-if [ $Name == "Daniya" ] || [ $Name == "Zach" ]
+if [ "$Name" == "Daniya" ] || [ "$Name" == "Zach" ]
 then
     echo "This will run if $Name is Daniya OR Zach."
 fi
@@ -121,6 +130,15 @@ ls -l # Lists every file and directory on a separate line
 # .txt files in the current directory:
 ls -l | grep "\.txt"
 
+# Since bash works in the context of a current directory, you might want to 
+# run your command in some other directory. We have cd for changing location:
+cd ~    # change to home directory
+cd ..   # go up one directory
+        # (^^say, from /home/username/Downloads to /home/username)
+cd /home/username/Documents   # change to specified directory
+cd ~/Documents/..    # still in home directory..isn't it??
+
+
 # You can redirect command input and output (stdin, stdout, and stderr).
 # Read from stdin until ^EOF$ and overwrite hello.py with the lines
 # between "EOF":