Linux Shells by Example

Table of contents

1. Copyright
2. PREFACE
3. Acknowldgements
4. About the Author
5. Introduction to Linux Shells
   1. Why Linux?
   2. Definition and Function of a Shell
   3. System Startup and the Login Shell
   4. Processes and the Shell
   5. The Environment and Inheritance
   6. Executing Commands from Scripts
6. The Linux Tool Box
   1. Regular Expressions
   2. Combining Regular Expression Metacharacters
7. The Grep Family (Gnu & Sons)
   1. The grep Command
   2. Extended grep (grep -E or egrep)
   3. Fixed grep (grep -F and fgrep)
   4. Recursive grep (rgrep)
   5. grep with Pipes
   6. grep with Options
   7. Linux Tools Lab 1
8. The Streamlined Editor
   1. What Is sed?
   2. Versions of sed
   3. How Does sed Work?
   4. Addressing
   5. Commands and Options
   6. Error Messages and Exit Status
   7. sed Examples
   8. sed Scripting
   9. LINUX TOOLS LAB 2
9. Gawk Utility: Gawk as a Linux Tool
   1. What's awk? What's nawk? What's gawk?
   2. awk's Format
   3. Formatting Output
   4. awk Commands from within a File
   5. Records and Fields
   6. Patterns and Actions
   7. Regular Expressions
   8. awk Commands in a Script File
   9. Review
   10. Linux Tools Lab 3
10. The Gawk Utility: Evaluating Expressions
    1. Comparison Expressions
    2. Review
    3. Linux Tools Lab 4
11. The Gawk Utility: Gawk Programming
    1. Variables
    2. Redirection and Pipes
    3. Pipes
    4. Closing Files and Pipes
    5. Review
    6. Linux TOOLS LAB 5
    7. Conditional Statements
    8. Loops
    9. Program Control Statements
    10. Arrays
    11. awk Built-In Functions
    12. User-Defined Functions
    13. Review
    14. Linux Tools Lab 6
    15. Odds and Ends
    16. Review
    17. Linux Tools Lab 7
12. The Interactive Bash Shell
    1. Introduction
    2. Command Line Shortcuts
    3. Variables
    4. The Bourne Shell Lab Exercises
13. Programming with the Bash Shell
    1. Introduction
    2. Reading User Input
    3. Arithmetic
    4. Positional Parameters and Command Line Arguments
    5. Conditional Constructs and Flow Control
    6. Looping Commands
    7. Functions
    8. Trapping Signals
    9. Debugging
    10. Processing Command Line Options with getopts
    11. The eval Command and Parsing the Command Line
    12. Bash Options
    13. Shell Built-In Commands
    14. The Bash Shell Lab Exercises
14. The Interactive TC Shell
    1. Introduction
    2. The TC Shell Environment
    3. Command Line Shortcuts
    4. Job Control
    5. Metacharacters
    6. Redirection and Pipes
    7. Variables
    8. Arrays
    9. Special Variables and Modifiers
    10. Command Substitution
    11. Quoting
    12. Built-In Commands
    13. The TC Shell Lab Exercises
15. Programming with the TC Shell
    1. Steps in Creating a Shell Script
    2. Reading User Input
    3. Arithmetic
    4. Debugging Scripts
    5. Command Line Arguments
    6. Flow Control and Conditional Constructs
    7. Loops
    8. Interrupt Handling
    9. setuid Scripts
    10. Storing Scripts
    11. Built-In Commands
    12. The TC Shell Lab Exercises
16. Useful Linux/UNIX Utilities for Shell Programmers
    1. apropos—searches the what is database for strings
    2. arch—prints the machine architecture (see uname -m)
    3. at—at, atq, atrmbatch—execute commands at a later time
    4. awk (gawk)—pattern scanning and processing language
    5. banner—make posters
    6. basename—with a directory name delivers portions of the pathname
    7. bash—Gnu Bourne Again Shell
    8. bc—processes precision arithmetic
    9. biff [ny]—be notified if mail arrives and who it is from
    10. cal—displays a calendar
    11. cat—concatenates and displays files
    12. chfn—change the finger information
    13. chmod—change the permissions mode of a file
    14. chown—change the user and group ownership of files
    15. chsh—change your login shell
    16. clear—clears the terminal screen
    17. cmp—compares two files
    18. compress—compress, uncompress, zcat compress, uncompress files, or display expanded files
    19. cp—copies files
    20. cpio—copy file archives in and out
    21. cron—the clock daemon
    22. crypt—encodes or decodes a file
    23. cut—removes selected fields or characters from each line of a file
    24. date—displays the date and time or sets the date
    25. dd—converts a file while copying it
    26. diff—compares two files for differences
    27. dos, xdos, dosexec, dosdebug—a Linux dos emulator that runs MS-DOS and MS-DOS programs under Linux
    28. df—summarizes free disk space
    29. du-summarizes disk usage
    30. echo—echoes arguments
    31. egrep—searches a file for a pattern using full regular expressions
    32. expr—evaluates arguments as an expression.
    33. fgrep—search a file for a character string
    34. file—determines the type of a file by looking at its contents
    35. find—finds files
    36. finger—displays information about local and remote users
    37. fmt—simple text formatters
    38. fold—folds long lines
    39. ftp—file transfer program
    40. free—displays amount of free and used memory in the system
    41. fuser—identifies processes using files or sockets
    42. gawk—pattern scanning and processing language
    43. gcc, g++—Gnu project C and C++ Compiler (v2.7)
    44. getopt(s)—parses command line options
    45. grep—searches a file for a pattern (See Chapter 3)
    46. groups—prints group membership of user
    47. gzip, gunzip, zcat—compresses or expands files
    48. head—outputs the first ten lines of a file(s)
    49. host—prints information about specified hosts or zones in DNS
    50. id—prints the username, user ID, group name, and group ID
    51. jsh—the standard, job control shell
    52. kill—sends a signal to terminate one or more processes
    53. killall—kills processes by name
    54. less—opposite of more
    55. line—reads one line
    56. ln—creates hard links to files
    57. logname—gets the name of the user running the process
    58. look—displays lines beginning with a given string
    59. lp (ATT, Linux)—sends output to a printer
    60. lpr (UCB, Linux)—sends output to a printer
    61. lpstat (ATT)—prints information about the status of the LP print service
    62. lpq (UCB, Linux)—prints information about the status of the printer
    63. ls, dir, vdir—lists contents of directory
    64. mail—mail, rmail—reads mail or send mail to users
    65. mailx—interactive message processing system
    66. make—maintains, updates, and regenerates groups of related programs and files
    67. man—formats and displays the online manual pages
    68. manpath—determines user's search path for man pages
    69. mesg—permits or denies messages resulting from the write command
    70. mkdir—creates a directory
    71. more—browses or pages through a text file
    72. mtools—utilities to access DOS disks in UNIX
    73. mv—moves or renames files
    74. nawk—pattern scanning and processing language
    75. newgrp—logs in to a new group
    76. news—prints news items
    77. nice—runs a command at low priority
    78. nohup—makes commands immune to hangups and quits
    79. od—dumps files in octal and other formats
    80. pack—pack, pcat, unpack—compresses and expands files
    81. passwd—changes the login password and password attributes
    82. paste—merges same lines of several files or subsequent lines of one file
    83. pcat—(see "pack" on page706)
    84. pine—a Program for Internet News and E-mail
    85. pg—displays files a page at a time
    86. pr—prints files
    87. ping—reports if a remote system is reachable and alive
    88. ps—reports process status
    89. pstree—displays a tree of processes
    90. pwd—displays the present working directory name
    91. quota—displays users' disk usage and limits
    92. rcp—remote file copy
    93. rdate—get the date and time via the network
    94. rgrep—a recursive, highlighting grep program
    95. rlogin—remote login
    96. rm—removes files from directories
    97. rmdir—removes a directory
    98. rsh—starts a remote shell
    99. ruptime—shows the host status of local machines
    100. rwho—who is logged in on local machines
    101. script—creates a typescript of a terminal session
    102. sed—stream editor (seeChapter 4)
    103. size—prints section sizes in bytes of object files
    104. sleep—suspends execution for some number of seconds
    105. sort—sort and/or merge files
    106. spell—finds spelling errors
    107. split—splits a file into pieces
    108. strings—finds any printable strings in an object or binary file
    109. stty—sets the options for a terminal
    110. su—become superuser or another user
    111. sum—calculates a checksum for a file
    112. sync—updates the superblock and sends changed blocks to disk
    113. tabs—sets tab stops on a terminal
    114. tail—displays the tail end of a file
    115. talk—allows you to talk to another user
    116. tar—stores and retrieves files from an archive file, normally a tape device
    117. tee—replicates the standard output
    118. telnet—communicates with a remote host
    119. test—evaluates an expression and check file types
    120. time—displays a summary of time used by this shell and its children
    121. timex—times a command; reports process data and system activity
    122. top—displays top CPU processes
    123. touch—updates access time and/or modification time of a file
    124. tput—initializes a terminal or queries the terminfo database
    125. tr—translates characters
    126. true—provides successful exit status
    127. tsort—topological sort
    128. tty—gets the name of the terminal
    129. umask—sets file-creation mode mask for permissions
    130. uname—prints name of current machine
    131. uncompress—restores files to their original state after they have been compressed using the compress command
    132. uniq—reports on duplicate lines in a file
    133. units—converts quantities expressed in standard scales to other scales
    134. unpack—expands files created by pack
    135. uucp—copies files to another system, UNIX-to-UNIX system copy
    136. uuencode—uuencode, uudecode—encodes a binary file into ASCII text in order to send it through e-mail, or convert it back into its original form
    137. wc—counts lines, words, and characters
    138. what—extracts SCCS version information from a file by printing information found after the @(#) pattern
    139. which (UCB)—locates a command and displays its pathname or alias
    140. whereis (UCB)—locates the binary, source, and manual page files for a command
    141. who—displays who is logged on the system
    142. write—writes a message to another user
    143. xargs—constructs an argument list(s) and executes a command
    144. zcat—uncompresses a compressed file to standard output. Same as uncompress –c
    145. zipinfo—lists detailed information about a ZIP archive
    146. zmore—file perusal filter for crt viewing of compressed text
17. Comparison of the Shells
    1. tcsh versus csh
    2. bash versus sh
18. Steps for Using Quoting Correctly
    1. Backslash (see Table C.1):
    2. Single Quotes (see Table C.1):
    3. Double Quotes (see Table C.2):
    4. Combining Quotes:
19. Index