backticks

I'd like to unit test a Perl program of mine that is using backticks. Is there a way to mock the backticks so that they would do something different from executing the external command? Another question shows what I need , but in Ruby. Unfortunately, I cannot choose to use Ruby for this project, nor do I want to avoid the backticks. You can * mock the built-in readpipe function. Perl will call your mock function when it encounters a backticks or qx expression. BEGIN { *CORE::GLOBAL::readpipe = \&mock_readpipe }; sub mock_readpipe { wantarray ? ("foo\n") : "foo\n"; } print readpipe("ls -R");

I need to execute the following code on a bash shell: mogrify -resize 800x600 *JPG Since the width and height are variables, I tried this: `mogrify -resize $widx$hit *JPG` However in compilation, I get the error that Global symbol "$widx" requires explicit package name at getattach.pl line 131. , which is because instead of $wid and x seperately, the compiler sees $widx as a new undeclared variable. I tried inserting double quotes inside the backticks, but execution of code stopped without any messages. What's the proper way of inserting variable names in backticks for shell execution? Can

Previously my all queries were running fine in CI version 2.0 but when I upgraded to 2.0.3 some of my SELECT queries were broken. CI is adding backticks (``) automatically, but in older version its running as it is. CI user manual have instructed to add second parameter in db->select as FALSE but still it's not working. Code is as following: class Company_model extends MY_Model { ---------------- $this->db->select(' count('.$fieldname. ') as num_stations'); $this->db->select(" CONCAT_WS(',', clb_company.address1, clb_company.address2, clb_company.city, clb_company.state, clb_company.zipcode )

in bash, if I execute a couple of commands piped together inside of backticks, how can I find out the exit status of the first command? i.e. in this case, I am trying to get the "1". which I can get via PIPESTATUS[0] if I am not using backticks, but which doesn't seem to work when I want to saving the output: ## PIPESTATUS[0] works to give me the exit status of 'false': $ false | true; $ echo $? ${PIPESTATUS[0]} ${PIPESTATUS[1]}; 0 1 0 ## doesn't work: $ a=`false | true`; $ echo $? ${PIPESTATUS[0]} ${PIPESTATUS[1]}; 0 0 More generally, I am trying to accomplish: save the last line of the

I saw a similar question in Stack Overflow pertaining to Android, but I was wondering whether I should use backticks (`) or double quotes (") - using Python - to select table names or rowid or what have you. I tried single quotes - like this select 'rowid', * from 'tbl' order by 'rowid' . The single quotes worked in some cases but not all. I learned to use double quotes or backticks, and I was looking at SQLite Database Browser and I noticed that it used backticks. I really like to put double quotes around my strings in Python because I'm coming from Java, so it is natural to do cursor.execute

This command succeeds $ PS1='$(date +%s) $ ' 1391380852 $ However if I add a newline it fails $ PS1='$(date +%s)\n$ ' bash: command substitution: line 1: syntax error near unexpected token `)' bash: command substitution: line 1: `date +%s)' If I use backticks it works $ PS1='`date +%s`\n$ ' 1391381008 $ but backticks are discouraged . So what is causing this error? GNU bash, version 4.2.45(6)-release You can disambiguate the parsing easily, to prevent hitting any such bug (though I can't reproduce it myself): PS1='$(date +%s)'$'\n$ ' This $'\n' syntax parses to a literal newline character,