Linux Command Summary
Command Synopsis Description
Release
Version 0.92 adduser adduser dsoneil | This command will automatically add a new user to the system
27.06.01 | The Bash script can be found in /usr/sbin if it needs to be changes
alias alias help=man | The alias command allows you to substitute a new name for a command
alias long=ls -al | An alias can also contain command line options
| Unless the alias definition is included in your .login file it is only temporary
apropos apropos keyword | Display command names based on keyword search
at at 1:23 lp /home/index.html | The at command runs a list of commands at a specified time (e.g. print @ 1:23)
Canadian Linux Users Group
at 1:50 echo “lp Job Done” | This uses the echo command to send a message at 1:50 saying a print job is done
at -l | Lists all scheduled jobs; an alias for the atq command
at -d 5555 | This will cancel job number 5555; an alias for the atrm command
batch Example: | Temporarily blank
cat cat /etc/filename | Prints specified file to the screen
cat file.a > file.b | Moves file.a to file.b
cat file.a > file.b | Appends the content of file.a to the end file.b
cd cd /home/dsoneil | Changes directories to the specified one
cd ~username | This will move you to the users specified home directory
chfn chfn dsoneil | This will allow you to change finger information on that user
| As an example it will allow you to change dsoneil to Darcy S. O’Neil
chmod chmod 666 filename | This command will give a file Read - Write permission for everyone
chmod 777 filename | This command gives Read - Write - Execute permission to everyone
chmod a=rwx file | This gives Read - Write - Execute permission to all users
For a complete listing of the available chmod permission commands please refer to Page 4 - Table 1
chown chown dso /home/html | This command will change the owner of the specified directory to dso
chown dso /home/file.a | This command will change the owner of the specified file to dso
clear clear | This will clear your screen
cmp cmp -s file.a file.b | Compares 2 files of any type. The -s option will return nothing in the files arethe same
cp cp file.a file.b | This will create a duplicate of file.a under a new file name, file.b
cpio ls /home | cpio -o > /root | This will copy the files of /home to the directory /root
cpio -it < /root > bk.indx | This will extract all of the files to /root and creates an index file called bk.indx
cpkgtool | Graphical front end to installpkg, removepkg, makepkg that uses ncurses.
cron |Comming Soon!
du du -k /home/html | Provides a summary of the disk space usage, in kb, within the specified path
du -k /home/html/file.a | Provides a summary of disk spaced used by a particular file
df df -h | Displays the total size, used and available space on all mounted file systems
fdformat fdformat /dev/fd0 | low level format of a floppy device in drive fd0
fdformat /dev/fd0H1440 | This will fromat a “Double Sided High Density”disk
file file file.a | This command will try to determine what type of file file.a is. (exec, text, etc.)
file -z file.a.tar | Looks inside a compressed file to determine it’s type.
file -L file.a | Follows symbolic links to be followed to determine file type
find find /path -name passwd | Locates the specified string (passwd), starting in the specified directory (/path)
| All filenames or directories containing the string will be printed to the screen
finger finger | This will list all users currently logged into the UNIX system
www.linux.ca
free free -t -o | Provides a snapshot of the system memory usage
fsck fsck /hda | file system check and repair
git | This is a file system viewer
grep cat /etc/passwd | grep dso | This searches for and limits the command output to the pattern specified
| In this case all instances of dso from the /etc/passwd file are printed
grep -i “Sample” /home/dsoneil | The -i option makes the search indifferent to case (e.g. sample or SAMPLE)
groupadd groupadd sudos | Create a new group called sudos on the system
groups groups | Shows which groups you are in
gzip gzip file.a | This will zip file.a and give it the extension file.a.gz
gzip -d file.a.gz | This will unzip the file file.a.gz
tar -zxvf file.a.tar.qz | The z flag allow you to decompress the tar file on the fly
hostname | Get or set hostname. Typically, the host name is stored in the file /etc/HOSTNAME.
Command Synopsis Description
Release
Version 0.92 adduser adduser dsoneil | This command will automatically add a new user to the system
27.06.01 | The Bash script can be found in /usr/sbin if it needs to be changes
alias alias help=man | The alias command allows you to substitute a new name for a command
alias long=ls -al | An alias can also contain command line options
| Unless the alias definition is included in your .login file it is only temporary
apropos apropos keyword | Display command names based on keyword search
at at 1:23 lp /home/index.html | The at command runs a list of commands at a specified time (e.g. print @ 1:23)
Canadian Linux Users Group
at 1:50 echo “lp Job Done” | This uses the echo command to send a message at 1:50 saying a print job is done
at -l | Lists all scheduled jobs; an alias for the atq command
at -d 5555 | This will cancel job number 5555; an alias for the atrm command
batch Example: | Temporarily blank
cat cat /etc/filename | Prints specified file to the screen
cat file.a > file.b | Moves file.a to file.b
cat file.a > file.b | Appends the content of file.a to the end file.b
cd cd /home/dsoneil | Changes directories to the specified one
cd ~username | This will move you to the users specified home directory
chfn chfn dsoneil | This will allow you to change finger information on that user
| As an example it will allow you to change dsoneil to Darcy S. O’Neil
chmod chmod 666 filename | This command will give a file Read - Write permission for everyone
chmod 777 filename | This command gives Read - Write - Execute permission to everyone
chmod a=rwx file | This gives Read - Write - Execute permission to all users
For a complete listing of the available chmod permission commands please refer to Page 4 - Table 1
chown chown dso /home/html | This command will change the owner of the specified directory to dso
chown dso /home/file.a | This command will change the owner of the specified file to dso
clear clear | This will clear your screen
cmp cmp -s file.a file.b | Compares 2 files of any type. The -s option will return nothing in the files arethe same
cp cp file.a file.b | This will create a duplicate of file.a under a new file name, file.b
cpio ls /home | cpio -o > /root | This will copy the files of /home to the directory /root
cpio -it < /root > bk.indx | This will extract all of the files to /root and creates an index file called bk.indx
cpkgtool | Graphical front end to installpkg, removepkg, makepkg that uses ncurses.
cron |Comming Soon!
du du -k /home/html | Provides a summary of the disk space usage, in kb, within the specified path
du -k /home/html/file.a | Provides a summary of disk spaced used by a particular file
df df -h | Displays the total size, used and available space on all mounted file systems
fdformat fdformat /dev/fd0 | low level format of a floppy device in drive fd0
fdformat /dev/fd0H1440 | This will fromat a “Double Sided High Density”disk
file file file.a | This command will try to determine what type of file file.a is. (exec, text, etc.)
file -z file.a.tar | Looks inside a compressed file to determine it’s type.
file -L file.a | Follows symbolic links to be followed to determine file type
find find /path -name passwd | Locates the specified string (passwd), starting in the specified directory (/path)
| All filenames or directories containing the string will be printed to the screen
finger finger | This will list all users currently logged into the UNIX system
www.linux.ca
free free -t -o | Provides a snapshot of the system memory usage
fsck fsck /hda | file system check and repair
git | This is a file system viewer
grep cat /etc/passwd | grep dso | This searches for and limits the command output to the pattern specified
| In this case all instances of dso from the /etc/passwd file are printed
grep -i “Sample” /home/dsoneil | The -i option makes the search indifferent to case (e.g. sample or SAMPLE)
groupadd groupadd sudos | Create a new group called sudos on the system
groups groups | Shows which groups you are in
gzip gzip file.a | This will zip file.a and give it the extension file.a.gz
gzip -d file.a.gz | This will unzip the file file.a.gz
tar -zxvf file.a.tar.qz | The z flag allow you to decompress the tar file on the fly
hostname | Get or set hostname. Typically, the host name is stored in the file /etc/HOSTNAME.
