Terminal Awareness

Just a general talk on being aware of how to work in the terminal, some basic scripting knowledge, and some tips, tricks and tools I picked up in about a year and a half of working nearly exclusively in a terminal.

No notes in this copy, which may make it a bit tough to follow

Transcript

1. Shell Scripting Lessons from a year administering remote machines
2. Basic Concepts
3. Shell Anatomy 101 • time php test.php 2>&1 | grep $NEEDLE > results.txt Shell Builtin Executables Arguments Redirection Pipe Environment Variable output
4. Process Pipes, a review Process stdin stdout stderr 2 1
5. 2>&1 Process stdin stdout stderr 2 1
6. Shell Anatomy 101 • time php test.php 2>&1 | grep $NEEDLE > results.txt Shell Builtin Executables Arguments Redirection Pipe Environment Variable output
7. Tools to Know About
8. man • read the manual page for a given command • $ man grep
9. cat • Puts the contents of a file onto stdout • $ cat “hello.txt”
 Hello, world
10. head/tail • Puts the beginning or end of a file on stdout • great for dealing with logs, especially with -f • $ tail -f /var/log/system.log
 Hello, world
11. ps • list information about processes • $ ps axu | grep grep
 bnicholas 4521 0.0 0.0 2453264 692 s000 S+ 10:26PM 0:00.00 grep grep
12. kill/killall • send a signal to processes by pid or name • $ kill -SIGUSR1 2048 • $ killall perl
13. sort • Takes lines from stdin and sorts them on stdout • $ cat file.txt | sort • $ cat numbers.txt | sort -n
14. uniq • Removes duplicate lines from stdin to stdout • $ cat file.txt | sort | uniq • $ cat ~/history | sort | uniq -c | sort -n
15. grep • Search for a regular expression • can be used on stdin or files • $ cat /var/log/product.log | grep -i “error”
16. tr • “trim” text, replacing characters with others • $ cat sentence.txt | tr ‘ ‘ ‘\n’
 My
 name
 is
 ben.
17. sed • stream editor: a mini text editor • Similar to vim find+replace syntax, but so much more too • $ echo “hello world!” | sed -e “s/ w.*d/bn.u/“
 hello bn.u!
18. find • A file finder with extra • $ find . -name “*.orig” -print - delete • $ find . -type f —mtime -1 -print
19. awk • a small programming language for dealing with columns • ps aux | grep grep | awk ‘{print $2}’
 6845
20. Control Flow
21. conditionals • if [ $VAR = “foo” ]
 then
 echo “bar”
 else
 echo “baz”
 fi
22. Better conditionals • Use && and || when possible • cat a.txt | grep “hello” && echo “world”
23. For loops • for FILE in `ls`
 do
 cat $FILE
 done
24. SSH The magic glue that holds things together
25. Key-based auth • More secure and convenient than passwords • ssh-copy-id <username>@<host> • Last time you’ll need to type a password • Also applies to git, scp, sftp, and others
26. ~/.ssh/config • Set up usernames across computers • Keep connections alive longer • Set up tunnels
27. Great Tricks/Tools
28. autocomplete
29. fish
30. ack http://beyondgrep.com
31. tmux
32. vim
33. dsh
34. Some example problems