Firebird Flight Wiki: Interacting with Files
Firebird Flight

Interacting with Files

In Linux, files can be read, created, or manipulated in a variety of ways. This guide introduces several commonly used commands and their most relevant flags. We’ll skip deep dives on redirection (>, >>) and piping (|) for a separate page, but you’ll still see them referenced in examples.

Contents
  1. Introduction
  2. Key Commands
    1. cat
    2. tail
    3. grep
    4. echo
    5. touch
    6. cp
    7. mv
    8. rm
  3. Conclusion

1. Introduction

Many day-to-day tasks revolve around reading, creating, or manipulating files. From quickly checking a file’s contents to copying or removing entire directories, these commands form the basis of Linux file operations.

2. Key Commands

Below is a collection of commands used for file interaction. Each includes a table of the most common flags or usage patterns.

2a. cat

The cat command reads the contents of a file (or multiple files) and outputs it to standard output. It’s commonly used to quickly display or concatenate file contents.

Usage / Flag Description
cat [file] Prints the contents of [file] to the screen.
cat file1 file2 Concatenates file1 and file2, outputting them together.
cat file1 > file2 Redirects the contents of file1 into file2 (overwrites file2).
Table 1: Common cat Usage

2b. tail

tail displays the last part of a file. It is particularly useful for monitoring logs in real time when combined with the -f option.

Flag / Usage Description
tail [file] Shows the last 10 lines of [file].
tail -n 20 [file] Shows the last 20 lines of [file].
tail -f [file] Follows [file] in real time, displaying new lines as they appear.
Table 2: Common tail Usage

2c. grep

grep searches for lines in a file (or stream) that match a given pattern. It’s frequently piped after other commands (e.g., ls | grep txt) to filter output.

Flag / Usage Description
grep [pattern] [file] Searches [file] for [pattern] and prints matching lines.
grep -i [pattern] [file] Case-insensitive search for [pattern].
grep -r [pattern] [dir] Recursively searches all files under [dir] for [pattern].
Table 3: Common grep Usage

2d. echo

echo outputs the given arguments to standard output. Often used in scripts or combined with redirection to create or append files.

Usage Description
echo "Hello World" Prints “Hello World” to the screen.
echo "New line" >> file.txt Appends “New line” to file.txt.
echo $PATH Prints the current PATH environment variable.
Table 4: Common echo Usage

2e. touch

touch creates new empty files or updates timestamps of existing ones. It’s handy for quickly generating placeholder files.

Flag / Usage Description
touch [filename] Creates [filename] if it doesn’t exist, or updates timestamps if it does.
touch file1 file2 Creates or updates multiple files at once.
Table 5: Common touch Usage

2f. cp

cp (copy) duplicates files or directories to a new location. By default, it leaves the original file(s) intact.

Flag / Usage Description
cp [source] [dest] Copies [source] to [dest]. Multiple files can be copied if [dest] is a directory.
cp -r [dir] [dest] Recursively copies the contents of [dir] to [dest].
cp -v [source] [dest] Verbose mode: prints each file as it’s copied.
Table 6: Common cp Usage

2g. mv

mv can relocate files or directories to another path, or rename them if the source and destination are in the same location.

Flag / Usage Description
mv [source] [dest] Moves (or renames) [source] to [dest].
mv -i [source] [dest] Interactive mode: prompts before overwriting an existing file.
mv -v [source] [dest] Verbose mode: prints each file as it’s moved or renamed.
Table 7: Common mv Usage

2h. rm

rm (remove) deletes files or directories. Use with caution, as deletions are typically permanent in Linux.

Flag / Usage Description
rm [file] Removes [file]. Cannot remove directories without -r.
rm -r [directory] Recursively removes a directory and all its contents.
rm -i [file] Interactive mode: asks for confirmation before removal.
Table 8: Common rm Usage

3. Conclusion

With these file-based commands, you can view, create, move, copy, and remove files as needed. In later topics, we’ll explore redirection, piping, and advanced text processing to further expand your control over file manipulation.