Baidu Linux pen questions

Baidu Linux-Linux general technology-Linux programming and kernel information. The following is a detailed description. 1. Extract the rows that contain "WARNING" or "FATAL" and do not contain "IGNOR" from the. log file, and then extract the 5th fields separated ":".

2. Write a script and only want to perform simple subtraction. A prompt is required to enter the variable.

3. Read the Shell script (explain the functions executed below). Pick out the errors in the following program or script and describe the errors.

#! /Bin/bash

# Monitor whether the point Port of cpuser is normal

Logname = "/home/forum/log/lpointlog. wf"

Flagfile = "/home/forum/log/lognum.txt"

Lodnum = sed-n "1, 1 p" $ flagfile

Newnum = wc-l $ {logname}

Echo $ newnum> $ flagfile

Totalnum = expr $ newnum-$ oldnum

Tail-n $ totalnum $ logname | grep "POINT_THREAD WARNING"

If [$? = 0]

Then

Mail-s "cpuser point" port exception. Please handle it! Test@aa.com
Fi>

A:

1. grep-invert-match "IGNOR" a. log | grep-line-number "WARNING \ | FATAL" | cut ':'-f 5 or

Grep-E 'Warning | fatal' file | grep-v ignor | awk-F ":" '{print $5 }'

2 .#! /Bin/bash

Read Arg1

Read Arg2

Result = 'expr $ Arg1-$ Arg2'

Echo $ Result or

#! /Bin/bash

Declare-rx SCRIPT =$ {0 ##*/}

Declare-ix NUM1

Declare-ix NUM2

Declare-ix NUM3

Read-p "input a number" NUM1

Read-p "input another number" NUM2

Let "NUM3 = NUM1-NUM2"

Printf "the result of $ NUM1 minus $ NUM2 is % d \ n" "$ NUM3"

3. Use reverse quotation marks to replace the command line. if [$? = 0] should be written as if [$? = 0], used to determine whether the last command was successfully executed;

The last line should be>/dev/null, And the last line after the fi is removed.