Shell Scripting Self Reflection

📍shell scripting is one of the automation tool.
📍Linux cli runs shell behind the scene.
📍Bash shell is one of the progam or software.
📍Shell takes the command and run on the top of CLI.
📍Why the need of shell increases..? Because mostly linux comes up with by default facility of shell.
📍chmod +x [script name] to make our script executable and then our script act as command.
📍: ( It is separator between two path ).
📍#! is termed as hashbang and shebang and it is instructor for shell.
📍$@: special variable where all the argument store.
📍Detail about iteration using for loop.
📍In linux tar command used for backup.
📍Detail about if else condition.
📍Operators: -eq, -ne, -gt, -lt, -ge, -le and test is used for checking conditions.
📍Detail about I/O redirection.
📍/dev/null is used as garbage.
📍Read work as a input in shell.
📍In linux cut command cut the lines.

📍In linux wc -l [file name]: shows no of line which is equals to no of hits.
📍awk: it is like cat command and specialized program, work on space separator by default. Here using -f : we can specify colon separator.
📍tail command in Linux show last lines.
📍-d? act as field separator or demililator.
📍Shell scripting to do word frequency.
📍echo, cd, history are function of shell but date, Cal are programs.
📍Creation of function, it has no meaning of exit code and we have to return it.
📍unset [ func name ] command to remove function.
📍 sed is used as string editor.