Week 5 – Redirections and Read/Write to Files

I. Redirections in bash commands

• stdin (standard input): This stream is used for input, such as keyboard input or input from a file.
• stdout (standard output): This stream is used for output, such as the results of a command or the contents of a file.
• stderr (standard error): This stream is used for error messages and other output that is not intended to be the primary output of a command.

II. Simple filter commands

• head: Prints the first few lines of a file or output.
• tail: Prints the last few lines of a file or output.
• cut: Extracts specific fields from the output of a command.
• sort: Sorts the output of a command.
• tr: Translates or deletes characters in the output of a command.
• wc: Counts the number of words, lines, or characters in the output of a command.

III. grep utility

IV. Redirection and piping

• Redirection: This allows you to redirect the output of a command to a file or to another command.
• Piping: This allows you to chain multiple commands together and pass the output of one command as the input to another command.

V. /dev/null file