Common Shell Routines

1. Iterate over each line in the file

 while read line;  Do Echo $line;  Done file. txt

Or

Cat file. txt | ( while read line;  Do echo $line; done)

Or

Cat file awk ' {print} '

2. Iterate over a word

 for inch $line;  Do Echo $word;  Done

3. WC statistics lines and characters

WC file // number of rows of statistics WC -wfile//  statistic number of words WCfile//  Statistical characters 

4. Linux at

The AT command is used to schedule a program to execute once in the future. All submitted tasks will be placed in the/var/spool/at directory and executed by the ATD Daemon at the time of execution

5. Identify the specific file

Find files that were modified 120 days ago in the/home directory

Find /home-mtime +

The/var directory to find files that have not been accessed within 90 days

find /var \! -atime-

Find files larger than 10MB in the/usr directory

Find /usr-size +10m

6. What is the use of the/proc file system?

The/proc file system is a memory-based file system that maintains information about the kernel state that is currently running. Includes CPU, memory, partition, IO address and other running processes. They are not files that actually store information, but instead point to in-memory information and are automatically maintained by the system.

Common Shell Routines