Bash Shell read file line and substring

#read Onefile Line by line forLineinch$(Cattest1.txt);  Do Echo$line; Done;# whileReadSplitLine by Space whileRead Line Do      forWordinch$line Do  Echo$word Done; Done<test1.txt#string Splitor substring input=type=ABCDEFGEcho$input, #get ABCDEFGEcho$input |Cut-D'='-F2Echo$input |Cut-D'='-F2#${variable:startindex:len}export str="123456789"Output=${STR:3:3}Echo$output #${varible##*stringthe string after the last string is truncated from left to right #${varible#*stringA string after the first string is truncated from left to right #${varible%%string*the string after the last string is intercepted from right to left #${varible%string*the string after the first string is truncated from right to left # common reserved variable: $HOME: Root path of the current user $path:path environment variable $PWD: Current working path $0,$1,$2,... : the No. 0 parameter (shell script itself), the 1th parameter ... $RANDOM:1-Integers between 65536

Bash Shell read file line and substring