Unix basic course 9 Standard Ibank O

1. Put it on / bin

2. Different characters and wildcards

? One character

* 0 or more characters (except for. The beginning of the file, ". *" this can show the hidden file)

$tail

^ head

[list] can match any character in list

[! list] does not match list

Ls ne?

Ls? e?

Ls n *

Rm *. * Delete a file containing at least one period

Rm * Delete all files

Rm report * Delete report, and then delete all files

3. Standard document

1) the place where the standard input stdin process gets input, usually the keyboard

2) the place where the standard output stdout process places the output, usually the screen

3) Standard error output stderr

4. File pointer

Every file has these three standards.

File pointer redirects symbol file

0

< stdin 1 >

Stdout

2 2 > stderr

Command

< file command >

File will overwrite

Command > > file append

/ dev/null black hole

Command

< infile >

Outfile 2 > errfile

Command > > appendfile 2 > > errfile

< infile command >

Outfile 2 > & 1

Pointer 1 first points to outfile,2 > error output to the position of pointer 1, that is, outfile

Command 2 > & 1 > outfile

Pointer 1 hasn't changed yet, so type it to the screen first.

Ls-l / * / * > list.file 2 > & 1

0 (unchanged) STDIN

1 (changed). / list.file

2 (changed). / list.file

Ls-l / * / * 2 > & 1 > list.file

0 (unchanged) STDIN

1 (changed). / list.file

2 (changed) STDOUT