General rule: quote it if it can either be empty or contain spaces (or any whitespace really) or special characters (wildcards). Not quoting strings with spaces often leads to the shell breaking apart a single argument into many. $? doesn’t need quotes since it’s a numeric value. Whether $URL needs it depends on what you … Read more
It’s a multi-character literal. 1952805748 is 0x74657374, which decomposes as 0x74 -> ‘t’ 0x65 -> ‘e’ 0x73 -> ‘s’ 0x74 -> ‘t’ Edit: C++ standard, §2.14.3/1 – Character literals (…) An ordinary character literal that contains more than one c-char is a multicharacter literal . A multicharacter literal has type int and implementation-defined value.
Single quotes are used to indicate the beginning and end of a string in SQL. Double quotes generally aren’t used in SQL, but that can vary from database to database. Stick to using single quotes. That’s the primary use anyway. You can use single quotes for a column alias — where you want the column … Read more
Have you tried: eval $cmd For the follow-on question of how to escape * since it has special meaning when it’s naked or in double quoted strings: use single quotes. MYSQL=’mysql AMORE -u username -ppassword -h localhost -e’ QUERY=”SELECT “‘*'” FROM amoreconfig” ;# <– “double”‘single'”double” eval $MYSQL “‘$QUERY'” Bonus: It also reads nice: eval mysql … Read more
Use a backslash: echo “\”” # Prints one ” character.
When PowerShell sees a command starting with a string it just evaluates the string, that is, it typically echos it to the screen, for example: PS> “Hello World” Hello World If you want PowerShell to interpret the string as a command name then use the call operator (&) like so: PS> & ‘C:\Program Files\IIS\Microsoft Web … Read more
Inside single quotes everything is preserved literally, without exception. That means you have to close the quotes, insert something, and then re-enter again. ‘before'”$variable”‘after’ ‘before'”‘”‘after’ ‘before’\”after’ Word concatenation is simply done by juxtaposition. As you can verify, each of the above lines is a single word to the shell. Quotes (single or double quotes, depending … Read more
String literals Escaping single quotes ‘ by doubling them up → ” is the standard way and works of course: ‘user’s log’ — incorrect syntax (unbalanced quote) ‘user”s log’ Plain single quotes (ASCII / UTF-8 code 39), mind you, not backticks `, which have no special purpose in Postgres (unlike certain other RDBMS) and not … Read more
After a brief review of the YAML cookbook cited in the question and some testing, here’s my interpretation: In general, you don’t need quotes. Use quotes to force a string, e.g. if your key or value is 10 but you want it to return a String and not a Fixnum, write ’10’ or “10”. Use … Read more
Backticks are to be used for table and column identifiers, but are only necessary when the identifier is a MySQL reserved keyword, or when the identifier contains whitespace characters or characters beyond a limited set (see below) It is often recommended to avoid using reserved keywords as column or table identifiers when possible, avoiding the … Read more