Linux command substitution: $ () "anti-quote"

 $() Introduction to Commands:

Replaces a subcommand in a command with the result of its execution.

1 . command format:

$ (Commond)

2 . Command function:

Replace a subcommand in the command with the result of its execution, and take advantage of the substitution result.

3 . Command parameters:

/

4 . Command instance:

1, touch./file-$ (date +%f-%h-%m-%s). txt to create a TXT document with the current time.

[[email protected] test]# touch./file-$ (date +%f-%h-%m-%s). txt

[[email protected] test]# ls

100.sh myar.sh showdisks.sh Test3.txt

File-2016-10-11-09-21-05.txt mytartest.tar.bz2 sum1.sh

2. Echo "$ (PWD)" Displays the current directory

[[email protected] test]# echo "$ (PWD)"

/test

' anti-quote Introduction to Commands:

Replaces a subcommand in a command with the result of its execution.

1 . command format:

' Commond '

2 . Command function:

Replace a subcommand in the command with the result of its execution, and take advantage of the substitution result.

3 . Command parameters:

/

4 . Command instance:

1, touch./file-' Date +%f-%h-%m-%s '. txt creates a TXT document with the current time.

[email protected] test]# touch/files. ' Date +%f-%h-%m-%s '. txt

[[email protected] test]# ls

100.sh mytartest.tar.bz2 sum1.sh until.sh

Files.2016-10-11-09-19-25.txt mytartest.tar.gz test1.txt while.sh

hadoop.sh q.tar.bz2 Test2.txt

myar.sh showdisks.sh Test3.txt

2. Echo ' pwd ' Displays the current directory

[[email protected] ~]# echo ' pwd '

/root

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Linux command substitution: $ () "anti-quote"