How does awk reference external variables?

Awk uses the following methods to reference external variables to call variables: www.2cto. com1.awk & amp; #39; {printa, B} & amp; #39; a111b222yourfile note: The variable must be placed before the file name; otherwise, it cannot be called. example: awk & amp; #39; {p... awk uses the following methods to reference external variables to call variables: www.2cto.com 1. awk '{print a, B} 'a = 111 B = 222 yourfile note that the variable location must be before the file name, otherwise it cannot be called. for example: awk '{print a, B} 'a = 111 file1 B = 222 file2file1 cannot call B = 222. also, variable cannot be called in BEGIN. it can be solved using the second method described later. www.2cto.com 2. awk-v a = 111-v B = 2 22 '{print a, B}' yourfile note: add a-v to each variable for transmission. 3. awk '{print "'" $ LOGNAME "'}' yourfile if you want to call environment variable, use the above method: (I add spaces to make it easy for everyone to understand) "'" $ LOGNAME "'" instance :#! /Bin/bash # This function lists the names of files whose names start with a date and are earlier than a certain date. It can be used to delete filtering curdate = 20110715 Filename = 'ls-l | awk-v cdate = $ curdate 'NR! = 1 & $8