Linux commands: CP, TIME, cut, awk, get file Size command

Recently wrote a shell script that used the CP, time, cut, and awk commands to write down their use methods:

1.CP and MV

CP command: Used to complete the copying of files from the source folder to the destination folder . Both the source and destination folders have source files after execution.

MV command: Used to move files. After execution, there is no source file in the source folder . I often use the MV command to rename files

Note: The CP command source folder cannot be the same as the destination folder, but it can be the same in MV.

Command parsing:

#cp [-r] Source file destination Folder

The CP-R parameter---used when copying the entire folder.

#mv Source File destination Folder

Command instance:

1.1 Copy a single file.

#cp/etc/init.d/rcs/tmp---Copy the RCS file of the INIT.D directory to the TMP directory, RCS is a file name of 1.2

1.2 Copy the folder.

#cp-R/etc/init.d//tmp---Copy all files in the INIT.D directory to the TMP directory INIT.D a folder name

1.3 Copy multiple files.

#cp/tmp/a*.txt/tmp/tmp---

1.4 File renaming

#mv/TMP/TEST1/TMP/TEST2---Speak the tmp folder under Test1 renamed to Test2.

1.5 Moving files

#mv/tmp/test1/home/kuaixiaoqian/test2---Move the test1 file under the/tmp folder to the/kuaixiaoqian folder and rename it to Test2

2.time command

function: used to calculate the execution time of a command.

format:time shell command

return form: after the execution result of the command under the shell, add the following statement:

2.1 Examples of Use:

(1) Easy to use

#time echo "Hello"

return Result:

(2) Save the time value to a file

# (Time echo "Hello") 2>time.txt ---Note: There can be no spaces between 2 and > in 2>time.txt

Execution Result:

3. Cut and awk commands

cut function : Cut each row of data, you can specify a delimiter (single character delimiter), and the field to get. Click here for details

awk function: separates each row of data with a space (which can be a contiguous number of spaces), and gets the specified value. The command is detailed here.

3.1 Examples of Use:

(1) Cut get file size

#ls-L Time.txt | cut-d '-f5 ---Note: Only when Ls-l is separated by a single space, cut takes a number of consecutive spaces to think of as multiple separators

Execution Result:

(2) awk gets the file size

#ls-L Time.txt | awk ' {print $} ' ---awk defaults to a space delimiter, and a contiguous number of spaces is considered a delimiter

Execution Result:

PS: I run a script on the embedded arm board, with the cut command does not get the file size correctly, a careful look only to find that is due to consecutive multiple spaces to separate the ls-l result of the cause