Collection of shell scripts

I. Replace text:

#1
Sed-I's/disabled = true/disabled = false/'/etc/fdfs/storage. conf
#2
Sed-I's/base_path = \/home \/yuqing \/fastdfs/base_path = \/fdfs \/storage/'/etc/fdfs/storage. conf
#3
Echo "Enter Tracker_IP :"
Read Tracker_IP
Echo "$ Tracker_IP"
Sed-I "/tracker_server/s/192.168.209.121/$ Tracker_IP/"/etc/fdfs/storage. conf
#4 if the value of tracker_server in the source file is not fixed, change it to the following statement:
Echo "Enter Tracker_IP :"
Read Tracker_IP
Echo "$ Tracker_IP"
Sed-I "/tracker_server/s/\ (. * = \). */\ 1 $ Tracker_IP/"/etc/fdfs/storage. conf

# This statement is incorrect:
Sed-I "s/tracker_server = 192.168.209.121/tracker_server = $ Tracker_IP/"/etc/fdfs/storage. conf


Ii. Insert text:

The following command inserts a specified line or multiple lines of text after B _IPadress 192.168.1.188
Sed-I '/B _IPadress 192.168.1.188/a \ test123'/root/my/myBin/sbin/test. config
Sed-I '/B _IPadress 192.168.1.188/s/$/\ nline1 \ nline2/'/root/my/myBin/sbin/test. config
Sed-I '/B _IPadress 192.168.1.188/a \ test123 \ n123 \ n123 \ n123'/root/my/myBin/sbin/test. config

If I replace a with I, multiple rows are inserted before the B _IPadress 192.168.1.188 row.


3. single quotation marks and double quotation marks:

Single quotes are strongly referenced. What are the values in quotes and the values of variables;
Double quotation marks are weak references. If the values in the quotation marks contain variables, all these variables will be replaced immediately when values are assigned.
For example:
Echo "who am I: $ LOGNAME" Result: who am I: yeexun
Echo "who am I: '$ logname'" Result: who am I: 'yeexun'
Echo "who am I:" $ LOGNAME "" Result: who am I: yeexun

Echo 'Who am I: $ logname' result: who am I: $ LOGNAME
Echo 'Who am I: "$ LOGNAME" 'result: who am I: "$ LOGNAME"
Echo 'Who am I: '$ logname' result: who am I: yeexun


4. Obtain the current row number based on the string and assign it to a variable. Then, insert text based on the row number.

1. Get the value-assigned variable of the row number.
Myline = $ (awk '/test123/{print NR}'/root/my/myBin/sbin/test. config)
2. Insert text based on the row number variable
Sed-I '3s/$/& \ a123/'a.txt
Sed-I ''$ myline's/$/& \ a \ nupstream fdfs_group1 {\ n server '$ tempvar': 8080; /'/root/my/myBin/sbin/test. config
Sed '3a 123 '1.txt
Sed-I ''$ myline 'a \ nupstream fdfs_group1 {\ n server '$ tempvar': 8080; '/root/my/myBin/sbin/test. config


V. Variable Calculation

Computation should be placed in square brackets
Known variable myline. The variable plus 2 should be written as: $ [myline + 2]


6. Replace the value of a string that appears for the first time

Unlimited:
Sed-e': a;/\ (. * ABC \) \ {3 \}/{s/ABC/DEF/3; q}; N; B'
ABC indicates the data before replacement, DEF indicates the data after replacement, and 3 indicates the first occurrence

There are restrictions (for example, title abcdefg, cannot have =, can only be a space)
Replace the data of the specified row: sed '0,/title/s/\ (title \). */\ 1 hello/'urfile
0 indicates the first appearance in the text


7. Replace the data of a specified row

Sed-I '2c \ storage_server_port = 100'/root/my/myBin/snbin/temp2


8. Total number of rows for saving files with variables

Temp = 'grep-c./root/my/myBin/snbin/temp2'

9. Delete the last few lines of the file

Delete the last row: sed-e '$ d' file
Delete the last few rows: Add the following statement to the for Loop


10. Others
When a shell value is assigned, there cannot be spaces before and after the equal sign
If conditions should be like this: if space [space $ tempvar0 Space = space "N" Space]
Basic knowledge: http://bbs.chinaunix.net/thread-452942-1-1.html