shell programming

summary

This chapter looks at Unix (and Linux) shell programming.

shell programming

This chapter looks at Unix (and Linux) shell programming.

You may wonder why a chapter on shell scripting is in a programming book. And you may not even read this line because your professor probably has cut this entire chapter out of the version used in your class.

There are actually several good reasons to include a chapter on shell scripting.

The chapter can serve as background material so that a student new to UNIX (or Linux or Mac OS X) will be able to make effective use of the shell for work on programming assignements.

There are actual classes in shell scipting, especially at junior colleges and community colleges.

This chapter goes beyond the typical material in a shell scripting class and presents material related to either downloading and compiling existing software (including ports to new hardware and/or operating systems) or for preparing your own software for release via the internet.

other

“22. A good system can’t have a weak command language.” —Alan Perlis, Epigrams on Programming, ACM’s SIGPLAN Notices Volume 17, No. 9, September 1982, pages 7-13

chapter contents

1. cool shell tricks
2. Unix/Linux history
3. choice of shells
4. connecting to a shell (Telnet and SSH; terminal emulator)
5. shell basics (book conventions; root or superuser; starting your shell; login and password; prompt; command example)
6. login/logout (login; select system; account name; password; terminal type; logout; exit)
7. passwd (setting password; local password; periodic changes; 100 most common passwords; secure passwords; superuser)
8. command structure (single command; who; failed command; date; options, switches, or flags; universal time; arguments; options and arguments; operators and special characters)
9. quick tour of shell commands
10. man (using man for help; man sections)
11. cat (creating files; example files for this book; viewing files; combining files)
12. command separator (semicolon)
13. less, more, pg last updated: 27 Aug 2012
14. file system basics (graphics examples; directory tree; important directories; home directory; parent and child directories; absolute paths; relative paths; dots, tildes, and slashes)
15. pwd
16. command history
17. built-in commands
18. ls
19. cd
20. cp
21. mv
22. rm (recursive)
23. shred
24. mkdir
25. alias
26. pipes
27. scripts
28. sysadmin and root/superuser
29. sudo and root
30. su
31. who
32. advanced file systems
33. major directories
34. Network File System (NFS)
35. tail
36. wc
37. chmod
38. chown
39. shell levels and subshells
40. substitutions
41. command substitutions
42. arithmetic substitutions
43. flow control
44. management tools
45. df
46. du
47. processes
48. ps
49. kill
50. nice
51. w
52. date
53. uname
54. uptime
55. top
56. lsof
57. free
58. vmstat
59. polkit
60. defaults (screencapture; Mac Flashback Trojan)
61. init (init; Linux run levels)
62. sendmail
63. ifconfig (view configuration; static IP address)
64. arp
65. netstat (view connections; main info; routing address)
66. route (view connections; routing commands)
67. ping (test packets; measuring)
68. nslookup
69. traceroute (entire route; etiquette)
70. ftp and sftp
71. cURL
72. sysstat
73. at (example; removing a job; timing)
74. back ups
75. tar
76. touch (multiple files; specific time)
77. find
78. text processing
79. basename
80. sed (fixing end of line; adding line numbers)
81. awk (remove duplicate lines)
82. screencapture (from graphic user interface; changing defaults; command line screenshots)
83. signals
84. LAMP
85. mysql
86. PHP
87. Perl
88. Tcl
89. Java
90. installing software from source
91. test bed
92. grep
93. ssh
94. vim
95. diff
96. sort
97. export
98. xargs
99. gzip
100. bzip2
101. unzip
102. shutdown
103. crontab
104. service
105. mount
106. whereis
107. whatis
108. locate
109. yum
110. rpm
111. wget
112. file permissions
113. nano
114. troff
115. command summaries
116. Forth-like routines