backticks

问题 I'm not a "command line" person by any means. I have been a front-end dev my entire career with little to no interaction with the command line, instead utilizing application GUIs as much as possible, so this may be a rather rudimentary question to many of you. I ran into a small issue when trying to commit with Git. I included the -m message flag and tried a message similar to "Example add function" with the word "add" surrounded by ` backtick symbols (can't show it here since doing that

问题 I'm trying to escape characters within backticks in my bash command, mainly to handle spaces in filenames which cause my command to fail. The command I have so far is: grep -Li badword `grep -lr goodword *` This command should result in a list of files that do not contain the word "badword" but do contain "goodword". 回答1: Your approach, even if you get the escaping right, will run into problems when the number of files output by the goodword grep reaches the limits on command-line length. It

问题 The problem is that: I have different txt files in which is registered a timestamp and an ip address for every malware packet that arrives to a server. What I want to do is create another txt file that shows, for every ip, the first time a malware packet arrives. In general I want to do something like this : for every line in file.txt if (ip is not present in list.txt) copy timestamp and ip in list.txt I'm using awk for doing it. The main problem is the "if ip is not present in list.txt". I'm

问题 This question already has answers here : How can I get the CPU time for a perl system call? (3 answers) Closed 2 years ago . I did lot of google to redirect the both STDOUT and STDERR of a program to a variable in perl, Initially i tried using both open and backticks , but failed to capture Error signal to the variable. I am posting this question because Now I got the solution and hope it may helps others.. 回答1: To get both STDOUT and STDERR into a variable use following code snippet using

问题 i'm trying to do shell command then save the output into variable using shell script. So i use backticks like this : out=`ls -l` print $out that code is working fine,and i can use it for any other shell command, but when i try to do 'python --version' to check python version. i got weird problem. The backtick is not working for "python --version" command while it's working fine with any other commands, it prints the output to the screen and save nothing to the variable $out. so if i do : out

问题 It seems that variables in backticks are not expanded when passed onto the readpipe function. If I override the readpipe function, how do I expand variables? BEGIN { *CORE::GLOBAL::readpipe = sub {print "Run:@_\n"}; } `ls /root`; my $dir = "/var"; `ls $dir`; Running this gives: Run:ls /root Run:ls $dir I am trying to mock external calls for a test code that I am writing. If there is a CPAN module somewhere which can help in taking care of all this, that would help too. Update : I have decided

问题 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

问题 I "inherited" some code in a project, and in one of the Bash scripts, they use echo on a backticks-row, like: #!/bin/bash echo `/path/command argument` What's the difference between that and just running the command itself? #!/bin/bash /path/command argument Both send the command's output to the script's stdout. So what's the difference? Why use echo ? To combine it with a > seems even worse: #!/bin/bash echo `/path/command argument > /var/log/exemple.log` 回答1: It doesn't look particularly

问题 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

问题 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 `; 回答1: No. That syntax is valid, but will just return a string containing \n// post id\nid , rather than removing the comments and creating a