Double hyphen bash
WebJun 10, 2024 · Another alternative that you shouldn't use that nobody listed : it's possible to escape the dash inside a quoted string so it is understood by grep as a literal character rather than the start of an option, i.e. echo test-test grep "\-test" will match rather than complain about an unknown -t flag. – Web5 Answers. A single hyphen can be followed by multiple single-character flags. A double hyphen prefixes a single, multicharacter option. In this example, -czf specifies three single-character flags: c, z, and f. In this case, --exclude specifies a single, multicharacter option named exclude.
Double hyphen bash
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Web2 Answers. Sorted by: 68. -- as an argument on its own is standardized across all UNIX commands: It means that further arguments should be treated as positional arguments, not options. See Guideline 10 in POSIX Utility Syntax Conventions. To give you a non-NPM-based example, ls -- -l will look for a file named -l, because the -- specified that ... WebFeb 17, 2024 · An alternative you can use instead of the double dash is -e. For example, grep -w -e -r (or grep -we -r) would have the same result as grep -w -- -r in the example above. -e allows specifying a search pattern, and it can be used to protect a pattern beginning with a dash (-).
WebDec 12, 2014 · 1 Answer. It's a parameter expansion, it means if the third argument is null or unset, replace it with what's after :-. There's also another similar PE that assign the value if the variable is null: Thanks for the explanation sputnick. Rather than "void", it's more accurate to say "unset or null". WebMay 3, 2016 · The CentOS 5 machine is running bash 3.2 (so is my Mac), while the CentOS 6 machine is running bash 4.1. I don't see anything in the bash changelog that indicates dropping support for - in variables names (or fixing a bug if such behavior was never meant to be allowed originally).
WebJan 22, 2024 · A double hyphen prefixes a single, multicharacter option. Consider this example: tar -czf In this example, -czf specifies three single-character flags: c, z, and f. So -c -z -f is same as -czf... WebSep 7, 2015 · So you really need to escape it twice (if you prefer not to use the other mentioned answers). The following will/should work. grep \\-X grep '\-X' grep "\-X". One way to try out how Bash passes arguments to a script/program is to create a .sh script that just echos all the arguments.
WebNov 26, 2024 · Let’s start gnome-terminal and run a sequence of bash commands inside using the ‘–‘ separator. The double hyphen ‘–‘ denotes the end of options to gnome-terminal. Everything after this mark is regarded as bash commands. So let’s run sleep inside a newly created terminal:
WebJan 23, 2024 · I'm reading a filename that has this data: 2024-03-23 2024-01-23 2024-07-31 I want to read each line and replace the hyphens with spaces. Given the above example, I should get the following: 201... ipanema rainbow baby shoeWebMar 20, 2024 · In Bash or PowerShell, both single and double quotes are interpreted correctly. In Windows Command Prompt, only double quotes are interpreted correctly -- single quotes are treated as part of the value. ... Use hyphen characters in parameters. If a parameter's value begins with a hyphen, Azure CLI tries to parse it as a parameter … open sky organic farmWebAug 16, 2016 · However, in general, double hyphens indicate a switch which is a full word, and single hyphens indicate a swich which is a single letter. And single-letter switches can be combined, which means that all of the following commands are equivalent: cp --verbose --recursive /dir/from /dir/to cp -v -r /dir/from /dir/to cp -vr /dir/from /dir/to. A ... open sky raptor foundationWeb949. More precisely, a double dash ( --) is used in most Bash built-in commands and many other commands to signify the end of command options, after which only positional arguments are accepted. Example use: Let's say you want to grep a file for the string -v. opensky secured business credit cardWebApr 3, 2024 · In fact, all Bash variables are just strings of characters. They are usually direct, single-quoted, or double-quoted sequences. Importantly, the difference between these methods is that we interpret or interpolate certain combinations of characters in one context and take them literally in another. 3.1. Single Quotes open sky recycling collectionsWebDec 4, 2024 · The meaning of --really depends on the program you are executing. In this example compgen.Check the documentation of this program, it should be explained there. A common convention that is not necessarily always followed is to treat everything after --as arguments, and do not try to parse as options or flags. As a concrete example, consider … open sky recycling scheduleWebSep 18, 2024 · Because double ampersands separate the two commands, Bash will only execute the second if the first succeeds. However, that’s the opposite of what we need. If the test for the “backup” directory succeeds, … ipanema street burns beach