Shell Learning Notes

1. number of logged-in users: who | Wc-l
2. See which users are logged on to the system : who
3. Create a new file /bin/ct11, enter a command in the file,chmod Set the Execute permission for the file

# cat >/bin/ct11

W.H.O. | Wc-l

Press Ctrl+d

# Cd/bin

# chmod +x ct11

#./ct11

Execution Result:

2

1. # echo escape sequence:

\c : Indicates that echo does not print the last line break symbol

\a : Warning character, usually the BEL character of ASCII

\b : Backspace

\f : Page Change

\ n : line break

\ r: Enter

\ t: Horizontal tab

\v: Vertical tab

\ \ : backslash character

\ODDD: Converts a character into a 3 -bit octal value

1. printf statement printf "I said '%s,%s1,%s2,%s3 ' \ n" This is my pen
2. Clear Screen :Clear
3. Echo input A text branch append to file cc11: echo-e "WERW\NSFSD" >>cc11
4. Remove the ASCII carriage return from the Aa.txt file and write the contents to file.txt

# tr-d ' \ R ' < Aa.txt > file.txt

1. Remove the carriage return from the Aa.txt file and then use the pipeline to sort its file contents and enter it into the file file.txt

# tr-d ' \ r ' <aa.txt | Sort >file.txt

1. turn off the ability to automatically print input characters Stty-echo
2. reply to the function of automatically printing input characters stty Echo
3. trace function set-x is to perform trace function open,set +x is turn off tracking function

Eg:cat > aa.sh

Set-x

Echo SS Echo

Set +x

Echo SDF Echo

Ctrl +d

Chmod +x aa.sh

./aa.sh Execution

1. Automated Test Course Catalog
4. Shell Pass Parameters

Create a new tst.sh script,

Nano-w tst.sh

The contents of the edit script are as follows, and then the first second parameter, and so on, is the file name parameter

#!/bin/sh

Name=$1

echo "My name is ${name}!"

Save Ctrl +o When edit is finished, Ctrl + C when exiting

Chmod +x tst.sh has execute permission for script

./tst.sh Zhang

Execution Result:

My name is Zhang

if it is vi mode edit mode press i, save and exit press ESC: wq!

17.

Shell Learning Notes