The while loop statement 95
Use of : to set infinite while loop 99
The until loop statement 101
The select loop statement 102
Exit the select loop statement 106
Using the break statement 108
Using the continue statement 110
Command substitution 113
Chapter 5 Challenges 115
Chapter 6: Shell Redirection
116
Input and Output 116
Standard input 117
Standard output 119
Standard error 120
Empty file creation 121
/ dev/ null discards unwanted output 122
Here documents 123
Here strings 125
Redirection of standard error 126
Redirection of standard output 128
Appending redirected output 129
Redirection of both standard error and output 129
Writing output to files 130
Assigns the file descriptor (fd) to file for output 132
Assigns the file descriptor (fd) to file for input 133
Closes the file descriptor (fd) 134
Opening the file descriptors for reading and writing 134
Reads from the file descriptor (fd) 135
Executes commands and send output to the file descriptor (fd) 138
Chapter 6 Challenges 144
Chapter 7: Pipes and Filters
145
Linking Commands 145
Multiple commands 146
Putting jobs in background 147
Pipes 149
How to use pipes to connect programs 150
