Special symbols in the shell

* Wildcard character (* for 0 or more arbitrary characters)

[[email protected] ~]# ls *.txt

A.txt

1. txt:

2. txt:

？ Represents only one arbitrary character

[email protected] ~]# Touch Testa[[email protected] ~]# touch Testb.txt[[email protected] ~]# ls-d test?test1 test2 tes T3 Testa

# This symbol in Linux indicates the meaning of the comment description, that is, the content behind the # Linux ignored.

[Email protected] ~]# abc=123 #aaaaa [[email protected] ~]# echo $ABC 123

\ de-ideographic character, restores the following special symbol (for example "*") to normal characters.

[[email protected] ~]# touch \ #1. Txt[[email protected] ~]# ls1,ipt #1. txt 2.txt a.txt INSTALL.LOG.SYSL Og1.ipt 1.txt anaconda-ks.cfg install.log pv[[email protected] ~]# ls \ #1. txt#1.txt

| The pipe character, which appears several times before, is the function of dropping the result of the preceding command to the command following the symbol

[email protected] ~]# cat Log.log |wc-l4

$ variable prefix (when you get, use the variable, add the symbol)
; Often used in the middle of two commands such as: LS 1.txt; LS 2.txt
~ User Home Directory
& Throw a command to the background such as: Sleep &
> Redirect >> Chase-weighted redirect 2> error redirect 2>> error append redirect
< Reverse redirect (the contents of the right document are redirected to the left command, such as Wc-l < 1.txt)
[] Two command set ls [12].txt equals ls 1.txt 2.txt regular expression is often used to define the range

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Special symbols in the shell