How can I modify text inside single quotes?

Question

I have a file that contains these lines:

war {
    baseName = 'myApp'
    version = '1.0.2'
}

And a variable like:

variable=b123

I want to edit the file appending $variable value to the version number so result will be:

war {
    baseName = 'myApp'
    version = '1.0.2_b123'
}

How achieve this goal with a bash script?

Answer 1

Would a simple sed do?

$ var=_b123
$ sed -Ee "/version/s/'(.*)'/'\1$var'/" file 
war {
    baseName = 'myApp'
    version = '1.0.2_b123'
}

(/version/ checks if the line contains that string, if it does we substitute a string inside single quotes with the same string ((...) captures, \1 restores) plus the text in the variable. The quoting is not an issue here since everything we need is safe within double-quotes.)

Answer 2

If you like vim, this works:

vim +/version +"norm 2f'i_b123" +x file

This opens the file and executes three commands:

• go to first line that contains "version"

• enter normal mode, go to the second ', go to insert mode, insert _b123

• write and quit