shell

问题 I thought C shell script will behave like C and use short circuit evaluation for logical operators. if ((! -e $cache ) || ("`find $monitor -newer $cache`" != "")) then ... endif But in the if statement, even if the first condition is true, the second is checked giving me errors. Do we have a short circuit logical OR in C shell script? 回答1: Usually, && and || are short-circut. Consider something like this: $ false && echo foo $ true || echo foo In both cases, foo won't be put out. But, AFAIK

问题 Need to print lines after the last match to the end of file. The number of matches could be anything and not definite. I have some text as shown below. MARKER aaa bbb ccc MARKER ddd eee fff MARKER ggg hhh iii MARKER jjj kkk lll Output desired is jjj kkk lll Do I use awk with RS and FS to get the desired output? 回答1: You can actually do it with awk (gawk) without using any pipe. $ awk -v RS='(^|\n)MARKER\n' 'END{printf "%s", $0}' file jjj kkk lll Explanations: You define your record separator

问题 I can't run a Conda command using exec with my NodeJS app. var conda_path = '~/miniconda3/bin/conda' var cmd = conda_path + ' init bash & ' + conda_path + ' activate XYZ' exec(command, function(error, stdout, stderr){ } ); I get the following error: /bin/sh: /Users/username/Desktop/repos/project/XYZ: is a directory CommandNotFoundError: Your shell has not been properly configured to use 'conda activate'. To initialize your shell, run $ conda init <SHELL_NAME> Currently supported shells are: -

问题 When executing a :make command that displays its content in a temporary vim buffer, is there any way to have these lines soft-wrapped at the edge of the terminal? Most console hosts do not have side scrolling and any long lines that come out of :make are completely truncated in vim (i.e. expanding the terminal width after-the-fact does not recover them). I'm not able to interact with the buffer containing the :make results in any meaningful way ( :set wrap or zl ) that would allow me to

问题 I have a simple func.php file with concat function: <?php function concat($arg1, $arg2) { return $arg1.$arg2; } ?> I would like to call this function from linux bash shell with two arguments : 1st: "Hello, " 2nd: "World!" and print the output ("Hello, World!") to linux bash shell. Please tell me, how to do it? 回答1: What you want is $argv So for example, your script would be called like this: php /path/to/script.php 'Hello, ' 'World!' Then in your PHP file: <?php $arg1 = $argv[1]; $arg2 =

问题 I often use ./*/ in a for loop like for d in ./*/; do : # do something with dirs done to match all non-hidden directories in current working directory, but I'm not really sure if this is a portable way to do that. I have bash, dash and ksh installed on my system and it works with all, but since POSIX spec doesn't say anything about it (or it says implicitly, and I missed it) I think I can't rely on it. I also checked POSIX bug reports, but to no avail, there's no mention of it there as well.

问题 I'm trying to read from two different inputs in nested loops without success. I've followed the best answer on this question and also took a look at the file descriptors page of the Advanced Bash-Scripting Guide . Sample script I made to test my problem. #!/bin/bash while read line <&3 ; do echo $line while read _line <&4 ; do echo $_line done 4< "sample-2.txt" done 3< "sample-1.txt" Content of sample-1.txt Foo Foo Content of sample-2.txt Bar Bar Expected output Foo Bar Bar Foo Bar Bar The

问题 Go has the support for variable expansion , for example: os.ExpandEnv("test- ${USER} ")` >> "test-MyName" But is there a way of expanding executables , as the way the shell behaves? Something like os.ExpandExecutable("test- $(date +%H:%M) ") >> "test-18:20" I cannot find an equivalent method for this, is there an elegant way of doing this instead of manually extracting the placeholders out, executing and then replacing them? 回答1: There's no built in function for this, but you can write a

问题 I need to start and restart a custom web server on travis. Starting in background is fine using a sub-shell ( .travis.yml ): - if [ "$TEST_ADAPTER" = "HTTP" ]; then (vendor/bin/httpd.php start &); fi To stop/kill the process again I'm trying to get its PID and then kill it: - if [ "$TEST_ADAPTER" = "HTTP" ]; then (vendor/bin/httpd.php start &) && SERVER_PID=$!; fi - ... - if [ "$TEST_ADAPTER" = "HTTP" ]; then kill -9 $SERVER_PID && ...; fi However, SERVER_PID is empty. What is the right way

问题 I have the following code that works great to run the ls command. I have a bash alias that I use alias ll='ls -alFGh' is it possible to get python to run the bash command without python loading my bash_alias file, parsing, and then actually running the full command? import subprocess command = "ls" # the shell command process = subprocess.Popen(command, stdout=subprocess.PIPE, stderr=None, shell=True) #Launch the shell command: output = process.communicate() print (output[0]) Trying with