Capture the AWK operation string

For AWK and Bash, they use different string index systems. the first character of bash is recorded from 0; the first character of awk is recorded from 1; #012345678 ------------ Bash #123456789 --------------- The following is a case study of Awk: [html] [root @ Slave02 shell] # vi substring-extraction.sh #! /Bin/bash String = 23skidoo1 echo $ {String: 2: 4} echo | awk '{print substr ("'" $ {String} "'", 3,4 )} 'Exit 0 ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ "Substring-extraction.sh" [New] 8L, using C written [root @ Slave02 shell] # sh substring-extraction.sh skid [root @ Slave02 shell] # Use the prefix of the variable to match all the variables previously declared; for example: [html] [root @ Slave02 shell] # xyz23 = watever [root @ Slave02 shell] # xyz24 = asdf [root @ Slave02 shell] # echo "a =$ {! Xyz *} "a = xyz23 xyz24 [root @ Slave02 shell] # echo" a =$ {! Xyz @} "a = xyz23 xyz24 [root @ Slave02 shell] # throwing dice games; SPOTS = 6 ----- mod 6, the value range is 0-5die1 = 0die2 = 0 ------------. Two variable names are available, make sure that the number records selected for each plane are the same. let "die1 = $ RANDOM % $ SPOTS + 1" let "die2 = $ RANDOM % $ SPOTS + 1" let "throw = $ die1 + $ die2 "echo" Throw of the dice = $ throw "echo exit 0 verification results below: [html] Random number greater than 200 --- 25552 Throw of the dice = 5 [root @ Slave02 shell] # [html] random number less than 500 --- 0 Ra Ndom number greater than 200 --- 9765 Throw of the dice = 2 [root @ Slave02 shell] # [html] Random number greater than 200 --- 31180 Throw of the dice = 10 [root @ Slave02 shell] # [root @ Slave02 shell] # sh random2.sh Random number between 0 and 1 = 0.246062 [root @ Slave02 shell] # sh random2.sh Random number between 0 and 1 = 0.619153 [root @ slave02 shell] # sh random2.sh Random number between 0 and 1 = 0.619 153 [root @ Slave02 shell] # sh random2.sh Random number between 0 and 1 = 0.619153 [root @ Slave02 shell] # sh random2.sh Random number between 0 and 1 = 0.619153 [root @ Slave02 shell] # sh random2.sh Random number between 0 and 1 = 0.201116 [root @ Slave02 shell] # cat random2.sh #! /Bin/bash AWKSCRIPT = '{srand (); print rand ()} '-srand pseudo-Random calculation echo-n "Random number between 0 and 1 =" echo | awk "$ AWKSCRIPT" exit 0 [root @ Slave02 shell] #