Lab 6: Input Output Redirection
Objective Focus
- Understand and use essential tools
- Create and edit text files
- Use input-output redirection (>, », |, 2>, etc.)
Official RHCSA EX200 Exam Objectives
Looking At File Content as Terminal Output
$ cat - concatenate files and print on the standard output
$ less - allows a user to partially display content of a file
$ more - has less options than $ less
$ head - output the first part of files, default is first 10 lines
$ tail - output the last part of files, default is last 10 lines
Understanding Input and Output Redirection
| Input | Output | Error |
|---|---|---|
| < | >, » | 2> |
| $ out < in | $ in > out | $ in 2> errout |
| $ in » out |
Example Use Cases
$ grep -i "error" < samplelog.txt Download sample file here!
$ ip a > pcinfo.txt $ hostname >> pcinfo.txt $ hostname123 2> errout.txt How to use pipes “|” in Linux
Using the “|” character is a form of redirection. It allows you to take output from one command to another.
$ cmd1 | cmd2 | cmd3 |.....|cmd_x Example Use Cases
$ ip a | grep -i "inet" | awk '{print $1,$2}'The above example shows us how we use available tools on the system for redirection. And how We could also redirect this output to a text file to share.
Redirections are very important to completing daily tasks in linux!
That’s it for lab 6!