backticks

Let's say I want to run an external program from my script with backticks and at the same time I want to capture both STDOUT and STDERR but in two different variables. How can I do that? For istance if I run this script... my $cmd = `snmpwalk -v $version -c $community $hostname $oid`; ...if there is no error everything works just fine BUT if the command raise an error this error will be printed on the command line and I don't want that to happen. I want to capture the error as well. Nothing has to be printed on the screen. Any ideas? Pablo Marin-Garcia In the Perl FAQ you have different

This question already has an answer here: What is the difference between $(command) and `command` in shell programming? 6 answers I see in bash scripts two different forms which seems to do the same: `some command` and $(some command) What is the difference between the two, and when should I use each one of them? There is no semantic difference. The backtick syntax is the older and less powerful version. See man bash , Section "Command Substitution". If your shell supports the $() syntax, prefer it because it can be nested. 来源： https://stackoverflow.com/questions/8941381/what-is-the-difference

(backtick) and ' are two different characters for single quote. I have a mysql script that shows the former two quote characters, if I change them to ', it breaks the syntax. how do I type ` from the keyboard? You are referring to the character commonly called a "backtick" ( ` ). It is not a single quote, although in some fonts it can look like one. It has a completely different meaning in MySQL than a single quote, as it is used to escape table and column names, whereas the single quote is used to enclose data values. It is at the top-left of your keyboard in all likelihood, often just to the

I have this macro, which rewrites define. If I remove the " ` " backtick it won't work. What is the explanation? (defmacro define ((name &rest r) body) `(defun ,name ,r ,body)) A single quote followed by the written representation of a value will produce that value: Example: '(1 x "foo") will produce a value that prints as (1 x "foo") . Suppose now that I don't want a literal symbol x in the list. I have a variable x in my program, and I want to insert the value to which x . To mark that I want the value of x rather than the symbol x , I insert a comma before x : '(1 ,x "foo") It won't work as

I am having a problem getting my shellscript working using backticks. Here is an example version of the script I am having an issue with: #!/bin/sh ECHO_TEXT="Echo this" ECHO_CMD="echo ${ECHO_TEXT} | awk -F' ' '{print \$1}'" result=`${ECHO_CMD}`; echo $result; result=`echo ${ECHO_TEXT} | awk -F' ' '{print \$1}'`; echo $result; The output of this script is: sh-3.2$ ./test.sh Echo this | awk -F' ' '{print $1}' Echo Why does the first backtick using a variable for the command not actually execute the full command but only returns the output of the first command along with the second command? I am

Let's say we have a multiline es6 Template-String to describe e.g. some URL params for a request: const fields = ` id, message, created_time, permalink_url, type `; Is there any way to have comments inside that backtick Template-String? Like: const fields = ` // post id id, // post status/message message, // ..... created_time, permalink_url, type `; No. That syntax is valid, but will just return a string containing \n// post id\nid , rather than removing the comments and creating a string without them. If you look at §11.8.6 of the spec , you can see that the only token recognized between the

For the command: /usr/bin/sh -c "ls 1`" (a backquote after 1). How to make it run successfully? Adding a backslash before "`" does not work. ` is a special char as we know, and I tried surrounding it with single quote too (/usr/bin/sh -c "ls 1'`'"), but that doesn't work either. The error always are: % /usr/bin/sh -c "ls 1\`" Unmatched ` You need to escape the backtick, but also escape the backslash: $ touch 1\` $ /bin/sh -c "ls 1\\\`" 1` The reason you have to escape it "twice" is because you're entering this command in an environment (such as a shell script) that interprets the double-quoted