1, Generate integers between consecutive numbers (including positive integers and negative integers)
[root@server51 ~]# seq --help Usage: seq [OPTION]... LAST or: seq [OPTION]... FIRST LAST or: seq [OPTION]... FIRST INCREMENT LAST Print numbers from FIRST to LAST, in steps of INCREMENT. -f, --format=FORMAT use printf style floating-point FORMAT -s, --separator=STRING use STRING to separate numbers (default: \n) -w, --equal-width equalize width by padding with leading zeroes --help display this help and exit --version output version information and exit
The above results show that there are - F, - s, - W options.
Without options, you can generate integers between two numbers, positive integers and negative integers:
[root@server51 ~]# seq 1 5 1 2 3 4 5 [root@server51 ~]# seq -5 -1 -5 -4 -3 -2 -1
-f option (format), format output:
[root@server51 ~]# seq -f "%3g" 1 5 1 2 3 4 5 [root@server51 ~]# seq -f "%03g" 1 5 001 002 003 004 005
-w option (width), specify the width output:
[root@server51 ~]# seq -w 1 05 01 02 03 04 05 [root@server51 ~]# seq -w 1 005 001 002 003 004 005 [root@server51 ~]# seq -w 001 5 001 002 003 004 005 [root@server51 ~]# seq -w 0001 5 0001 0002 0003 0004 0005
-s option (separator), specifying that the separator is line feed by default:
[root@server51 ~]# seq 1 5 1 2 3 4 5 [root@server51 ~]# seq -s "" 1 5 12345 [root@server51 ~]# seq -s " " 1 5 1 2 3 4 5 [root@server51 ~]# seq -s "`echo -e "\t"`" 1 5 1 2 3 4 5
2, Generate random number
Generate random numbers within 1-10
[root@server51 ~]# expr $[RANDOM%10+1] 8 [root@server51 ~]# expr $[RANDOM%10+1] 5 [root@server51 ~]# expr $[RANDOM%10+1] 5 [root@server51 ~]# expr $[RANDOM%10+1] 8 [root@server51 ~]# expr $[RANDOM%10+1] 7 [root@server51 ~]# expr $[RANDOM%10+1] 5 [root@server51 ~]# expr $[RANDOM%10+1] 3
expr $[RANDOM%10] will generate a random number between 1 and 9