- bash - What are the special dollar sign shell variables . . . - Stack . . .
In Bash, there appear to be several variables which hold special, consistently-meaning values For instance, myprogram amp;; echo $! will return the PID of the process which backgrounded myprog
- bash - What is the purpose of in a shell command? - Stack Overflow
$ command one command two the intent is to execute the command that follows the only if the first command is successful This is idiomatic of Posix shells, and not only found in Bash It intends to prevent the running of the second process if the first fails You may notice I've used the word "intent" - that's for good reason
- bash - Shell equality operators (=, ==, -eq) - Stack Overflow
It depends on the Test Construct around the operator Your options are double parentheses, double brackets, single brackets, or test If you use ((…)), you are testing arithmetic equality with == as in C: $ (( 1==1 )); echo $? 0 $ (( 1==2 )); echo $? 1 (Note: 0 means true in the Unix sense and a failed test results in a non-zero number ) Using -eq inside of double parentheses is a syntax
- Whats the difference between lt; lt;, lt; lt; lt; and lt; lt; in bash?
What's the difference between <<, <<< and < < in bash?Here document << is known as here-document structure You let the program know what will be the ending text, and whenever that delimiter is seen, the program will read all the stuff you've given to the program as input and perform a task upon it Here's what I mean: $ wc << EOF > one two three > four five > EOF 2 5 24 In this example we
- How do I iterate over a range of numbers defined by variables in Bash?
Related discusions: bash for loop: a range of numbers and unix stackexchange com - In bash, is it possible to use an integer variable in the loop control of a for loop?
- bash - Difference between if -e and if -f - Stack Overflow
59 $ man bash -e file True if file exists -f file True if file exists and is a regular file A regular file is something that isn't a directory, symlink, socket, device, etc
- Bash scripting missing ] - Stack Overflow
Bash scripting missing ']' [closed] Asked 12 years, 2 months ago Modified 4 years, 11 months ago Viewed 195k times
- linux - What does bash -c do? - Stack Overflow
152 Quoting from man bash: -c string If the -c option is present, then commands are read from string If there are arguments after the string, they are assigned to the positional parameters, starting with $0
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