UNIX Basic Commands

Linux Basic Commands • File Handling
• Text Processing
• System Administration
• Process Management
• Archival
• Network
• File Systems
• Advanced Commands
File Handling commands
• mkdir – make directories
Usage: mkdir [OPTION] DIRECTORY...
eg. mkdir prabhat
• ls – list directory contents
Usage: ls [OPTION]... [FILE]...
eg. ls, ls l,
ls prabhat
• cd – changes directories
Usage: cd [DIRECTORY]
eg. cd prabhat
• pwd print
name of current working directory
Usage: pwd
• vim – Vi Improved, a programmers text editor
Usage: vim [OPTION] [file]...
eg. vim file1.txt

* cp – copy files and directories
Usage: cp [OPTION]... SOURCE DEST
eg. cp sample.txt sample_copy.txt
cp sample_copy.txt target_dir
* mv – move (rename) files
Usage: mv [OPTION]... SOURCE DEST
eg. mv source.txt target_dir
mv old.txt new.txt

• rm remove
files or directories
Usage: rm [OPTION]... FILE...
eg. rm file1.txt , rm rf
some_dir
• find – search for files in a directory hierarchy
Usage: find [OPTION] [path] [pattern]
eg. find file1.txt, find name
file1.txt
• history – prints recently used commands
Usage: history
Pattern

A Pattern is an expression that describes a set of strings which is used to give a concise description of a set, without having to list all elements.
eg. ab*cd matches anything that starts with ab and
ends with cd etc.
ls *.txt – prints all text files

Text Processing
• cat – concatenate files and print on the standard output
Usage: cat [OPTION] [FILE]...
eg. cat file1.txt file2.txt
cat n
file1.txt
• echo – display a line of text
Usage: echo [OPTION] [string] ...
eg. echo I love India
echo $HOME

• grep print
lines matching a pattern
Usage: grep [OPTION] PATTERN [FILE]...
eg. grep i
apple sample.txt
• wc print
the number of newlines, words, and bytes in files
Usage: wc [OPTION]... [FILE]...
eg. wc file1.txt
wc L
file1.txt

• sort – sort lines of text files
Usage: sort [OPTION]... [FILE]...
eg. sort file1.txt
sort r
file1.txt

Linux File Permissions
• 3 types of file permissions – read, write, execute
• 10 bit format from 'ls l'
command
1 2 3 4 5 6 7 8 9 10
file type owner group others
eg. drwxrwrmeans
owner has all three permissions,
group has read and write, others have only read
permission
• read permission – 4, write – 2, execute 1
eg. rwxrwr=
764
673 = rwrwxwx

System Administration
• chmod – change file access permissions
Usage: chmod [OPTION] [MODE] [FILE]
eg. chmod 744 calculate.sh
• chown – change file owner and group
Usage: chown [OPTION]... OWNER[:[GROUP]] FILE...
eg. chown remo myfile.txt

• su – change user ID or become superuser
Usage: su [OPTION] [LOGIN]
eg. su remo, su
• passwd – update a user’s authentication tokens(s)
Usage: passwd [OPTION]
eg. passwd
• who – show who is logged on
Usage: who [OPTION]
eg. who , who b, who q

Process Management
• ps – report a snapshot of the current processes
Usage: ps [OPTION]
eg. ps, ps el
• kill – to kill a process(using signal mechanism)
Usage: kill [OPTION] pid
eg. kill 9
2275

• tar – to archive a file
Usage: tar [OPTION] DEST SOURCE
eg. tar cvf
/home/archive.tar /home/original
tar xvf
/home/archive.tar
• zip – package and compress (archive) files
Usage: zip [OPTION] DEST SOURSE
eg. zip original.zip original
• unzip – list, test and extract compressed files in a ZIP archive
Usage: unzip filename
eg. unzip original.zip