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  1. bash - What are the special dollar sign shell variables ... - Stack ...

    Sep 14, 2012 · In Bash, there appear to be several variables which hold special, consistently-meaning values. For instance, ./myprogram &; echo $! will return the PID of the process …

  2. shell - Bash regex =~ operator - Stack Overflow

    Oct 18, 2013 · What is the operator =~ called? I'm not sure it has a name. The bash documentation just calls it the =~ operator. Is it only used to compare the right side against the …

  3. bash - What is the purpose of "&&" in a shell command? - Stack …

    Oct 27, 2021 · Furthermore, you also have || which is the logical or, and also ; which is just a separator which doesn't care what happend to the command before.

  4. What does $# mean in bash? - Ask Ubuntu

    Jul 25, 2017 · Furthermore, when you use bash -c, behavior is different than if you run an executable shell script, because in the latter case the argument with index 0 is the shell …

  5. bash - Shell equality operators (=, ==, -eq) - Stack Overflow

    529 = and == are for string comparisons -eq is for numeric comparisons -eq is in the same family as -lt, -le, -gt, -ge, and -ne == is specific to bash (not present in sh (Bourne shell), ...). Using …

  6. bash - What does <<< mean? - Unix & Linux Stack Exchange

    Take a look at the Bash man page. This notation is part of what's called a here documents & here strings. It allows you the ability to generate multi-line data input as one continuous string. The …

  7. bash - What does $ ( ... ) mean in the shell? - Unix & Linux Stack …

    Sep 3, 2017 · For understanding bash code it is usually very helpful to set the -x option: set -x # within a script / function or when calling a script: bash -vx ./script.sh With loops this is a little …

  8. Meaning of $? (dollar question mark) in shell scripts

    Aug 1, 2019 · What does echo $? mean in shell programming?true echo $? # echoes 0 false echo $? # echoes 1 From the manual: (acessible by calling man bash in your shell) ? Expands to …

  9. Bash test: what does "=~" do? - Unix & Linux Stack Exchange

    Jan 27, 2017 · I realize you said “read the bash man pages” but at first, I thought you meant read the man pages within bash. At any rate, man bash returns a huge file, which is 4139 lines (72 …

  10. bash - Difference between >> and - Unix & Linux Stack Exchange

    In general, in bash and other shells, you escape special characters using \. So, when you use echo foo >\> what you are saying is "redirect to a file called > ", but that is because you are …