TCL脚本中使用的regexp表达式中的变量不匹配

Question

The below code snippet fetches the agent container ID from the docket host and matches it with the container ID obtained on logging into agent container. This was written to validate if the agent container login is successful

   set var_op1 [VIR-APP exec "docker ps -aqf \"name=agent\""]

   set docker_op [VIR-APP exec "docker exec -it agent /bin/bash"]

   set var_op2 [VIR-APP exec "uname -a"]

   set result [regexp -nocase ".*$var_op1.*" $var_op2 match]

The regular expression i put is not matching.Could someone help?

Answer 1

In this case, you can check for if a string is inside another string more simply with the string first command:

if {[string first $var_op1 $var_op2] >= 0} {
    # The $var_op1 string was found inside $var_op2
}

However you might find that this fails because the result of retrieving the value in var_op1 contains extra whitespace (eg, a trailing newline character). Because of that, you probably want to actually do:

if {[string first [string trim $var_op1] $var_op2] >= 0} {
    # The $var_op1 string was found inside $var_op2
}

(I believe that this is what is causing you problems with the regexp search, but any additional metadata characters would also cause problems; it's better to use string first here. Failing that, there's also string match , which uses glob-style matching such as most people are familiar with from filename handling, but that's a less correct tool right here.)