wc, grep, tar, vi/vim

One, wc

Command format:

wc [options]... target file.. (without options, the default count of lines, words, and bytes)

• -l: count lines
• -w: count the number of words
• -c: count bytes

[[email protected] test]# wc -l 1.txt //Count the number of lines, note that blank lines will also be counted4 1.txt[[email protected] test]# wc -w 1.txt //Count the number of words3 1.txt[[email protected] test]# wc -c 1.txt //Count the number of bytes, note that newline characters will also be counted13 1.txt[[email protected] test]# wc 1.txt //Do not specify options, the default lwc is displayed4 3 13 1.txt

Second, grep

grep is used to find matching strings in a file.

Command format

grep [options]… search criteria target file

• ^..." means start with..., "...$" means end with...
• "^$" means blank line

Use -i "^a" to retrieve the line starting with a, and it is not case-sensitive

[[email protected] ~]# grep -i "^a" /etc/passwdadm:x:3:4:adm:/var/adm:/sbin/nologinabrt:x:173:173::/etc/abrt:/sbin/nologinavahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologinalice:x:1002:1003::/home/alice:/bin/bashAmy:x:1005:1006::/home/Amy:/bin/bash

Use -v "^$" to filter out non-empty lines

[[email protected] test]# cat 123.txt //View the content of the 123.txt file111​222aaa[[email protected] test]# grep -v "^$" 123.txt //Filter out non-empty lines111222aaa[[email protected] ~]# cat 123.txt |grep -v '^$' >test.txt //Write non-empty lines to the test.txt file[[email protected] test]# cat test.txt //View test.txt111222aaa

Three, tar

Command format:

tar [options] ... archive filename (tarball name) source file or directory tar [options] ... archive filename [-C target directory]

• -c: Create a package file in .tar format
• -x: Unpack the package file in .tar format
• -C: Specify the target folder to be released when decompressing, specify the directory
• -f: Indicates the use of archive files (usually must be brought to indicate the use of tar)
• -v: output verbose information (Verbose)
• -t: list archive contents
• -j: call bzip2 program to compress or decompress
• -z: call the gzip program to compress or decompress

[[email protected] data]# tar -zcvf vm.tar.gz f1 f2 f3 //Archive the three files and call the gzip program to compress them into vm.tar.gzf1f2f3[[email protected] data]# tar -jcvf vm.tar.bz f1 f2 f3 //Archive the three files and call the bzip2 program to compress them into vm.tar.bz2f1f2f3​[[email protected] data]# tar -zxvf vm.tar.gz -C /opt //Extract the vm.tar.gz file to the /opt directoryf1f2f3​[[email protected] data]# tar -tf ff.tar.gzip //List archive contentsfile01file02​[[email protected] data]# tar -tvf /tmp/ceshi/ff.tar //List all files in the archive in detail (including attribute information)-rwxr--r-- root/root 87 2022-01-21 17:37 file01-rw-r--r-- user01/hr 0 2022-01-19 17:01 file02​

Four, vi/vim

vim is a text editor developed from vi.The functions of convenient programming such as code completion, compilation and error jumping are particularly rich, and are widely used by programmers.vim is an enhanced version of the vi text editor.

  1.Three working modes of the vim editor

Command mode: After starting the vi editor, it enters the command mode by default. This mode mainly completes related operations such as cursor movement, string search, and deletion, copying, and pasting of file contents;

Input mode: The main operation in this mode is to input the content of the file, you can modify the text of the text file, or add new content.When in input mode, the last line of the vi editor will display a status prompt of "--INSERT--";

Last line mode: In this mode, you can set the vi editing environment, save the file, exit the editor, and perform operations such as searching and replacing the file content.When in last line mode, a colon ":" prompt appears on the last line of the vi editor.

2. Basic operations in command mode

3. Basic operations in last line mode