Shell Scripting compilation

First, replace the 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 assume the value of the above Tracker_server in the source file is not fixed. Should be changed to the following wording:
echo "Enter tracker_ip:"
Read Tracker_ip
echo "$Tracker _ip"
Sed-i "/tracker_server/s/\ (. *=\). */\1$tracker_ip/"/etc/fdfs/storage.conf

# # This is not the correct way to do this:
Sed-i "s/tracker_server=192.168.209.121/tracker_server= $Tracker _ip/"/etc/fdfs/storage.conf


Second, insert the text:

The following command can insert a specified line or multiline of text after b_ipadress 192.168.1.188 the line
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 were to replace the middle A with I, I would insert multiple lines in front of the b_ipadress 192.168.1.188 line.


Three, single and double cited:

A single argument is a strong reference, what is the value in the argument, and what is the value of the variable;
The double argument is a weak reference. If the value in the argument is included again, all of these variables are replaced immediately when the value is assigned.

Like what:
echo "Who am I: $LOGNAME" results: Who am I:yeexun
echo "Who am I: ' $LOGNAME '" results: Who am I: ' Yeexun '
echo "Who am I:" $LOGNAME "results: Who am I:yeexun

Echo ' Who am I: $LOGNAME ' results: Who am I: $LOGNAME
Echo ' Who am I: ' $LOGNAME ' results: Who am I: ' $LOGNAME '
Echo ' Who am I: ' $LOGNAME ' results: Who am I:yeexun


Get the current line number from the string and assign it to a variable, and then insert the text based on the derived variable line number

1. Get the row number assignment variable
myline=$ (awk '/test123/{print NR} '/root/my/mybin/sbin/test.config)
2. Insert text according to the line 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


Five, the operation of the variable

The operation should be placed in square brackets
Known variable myline, the variable plus 2 should be written as: $[myline+2]


Vi. Replace the value of a string that appears several times

Unlimited:
Sed-e ': a;/\ (. *abc\) \{3\}/{s/abc/def/3;q}; N;b a '
ABC represents the pre-replacement data, DEF is the replacement data, 3 is the first occurrence

There are restrictions (such as: Title ABCDEFG. Cannot have =. Can only be a space)
Replaces the data for the specified row: sed ' 0,/title/s/\ (title \). */\1hello/' Urfile
0 indicates the first occurrence in the text


Vii. replacing data for a specified row

Sed-i ' 2c\storage_server_port=11111 '/ROOT/MY/MYBIN/SNBIN/TEMP2


Eight, the variable save the total number of files

Temp= ' Grep-c. /ROOT/MY/MYBIN/SNBIN/TEMP2 '

Nine, delete the last few lines of the file

Delete last line: Sed-e ' $d ' file
Delete last few lines: statement with a For loop plus polygon


X. Other
When the shell is assigned a value. Cannot have spaces before and after the equals sign
If condition should be like this: if space [space $tempvar0 space = = Space "N" space]
Basic knowledge: http://bbs.chinaunix.net/thread-452942-1-1.html

Shell Scripting compilation