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60 Cards in this Set
- Front
- Back
list files - long listing - displays inode number in the first field - displays number on file system blocks used by file -list all files including invisible files |
ls -l -i -s -a |
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displays on-line manual pages about command |
man |
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clears the current screen, giving you an emtpy terminal window |
clear |
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displays text files a page at a time allows backward movement, one page at a time initiates a search for a string exits from less advances one screen at a time advances one line at a time |
less b / q spacebar enter |
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searches a file or files for lines that contain strings of a certain pattern |
grep |
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creates a new user or updates default new user information specifies path of the user's home directory makes a home directory if one does not already exist assigns whatever group is in the default |
useradd -d -m -n |
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deletes a user account removes home directory for specified user |
userdel -r |
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enables a user to change their password or for the administrator to set and modify password settings |
passwd |
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switch user |
su |
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used for authentication and authorization |
etc/passwd |
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used for authentication |
etc/shadow |
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used for authorization |
etc/group |
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/etc/passwd File |
1. User Account Name 2. Placeholder for hashed password 3. User Identification Number 4. Group Identification Number 5. Comments 6. User's Home Directory 7. User's Default Shell |
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/etc/shadow File |
1. User Account Name 2. Hashed Password 3. Number of days between 01Jan1970 and last modification date - when last changed. 4. Minimum number of days between password changes. 5. Maximum number of days a password is valid. 6. Number of warning days until is user is required to change password 7. Number of days after password expires, account is disabled/inactive 8. Number of days from 01Jan1970 until account expires |
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/etc/group File |
1. Group Name 2. Placeholder for encrypted password 3. Group ID number 4. Users who have this group as a supplementary group |
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when user logs onto system for first time and doesn't have a profile, default settings |
/etc/profile |
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Users customize their environment/profile by modifying |
~/.bash_profile |
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System administration and configuration files |
/etc |
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Current working directory |
pwd |
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view the path statement modify path statement |
echo PATH=$PATH: |
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creates a typescript of the terminal session |
script |
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prints system information - prints all information |
uname -a |
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list directory contents in a tree-like format Turn colorization on always Append a "/" for directories |
tree -C -F |
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creates an empty file - manipulates files access date/time stamp |
touch -t |
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creates link between files or directories -creates symbolic link to another file |
ln -s |
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creates one or more directories - creates a directory where no parent directory exist |
mkdir -p |
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copies to a file or copies multiple files to a directory - recusively copies directories |
cp -R |
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Moves or renames files and directories |
mv |
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removes an empty directory |
rmdir |
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removes a file - removies a directory and its contents recursively -ignores nonexistent files, never prompt |
rm -r -f |
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creates or edits a text file |
vi <filename> |
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displays the contents one screen at a time |
more |
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called pipe, passes the output of one command to the input of another |
| |
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displays the first 10 lines of a file by default |
head <filename> |
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displays the last 10 lines of a file by default |
tail <filename> |
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displays file(s) conctents to the screen and can concatenate (combine) files |
cate <filename> <other_filename> |
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redirects standard output to a file. If the file does not exist, it is created. If the file does exist, it is overwritten |
> ex: cat <filename1> <filename2> > <bothfiles> |
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Appends standard output to the end of another file. If the file does not exist, it is created. |
>> ex: cat <filename1> >> <new file> |
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locates files having certain characteristics, which are specified |
find |
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displays the full path <location) of most (shell) commands |
which <command> |
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Displays a snapshot status of all active processes the terminal controls - list information about every process running - present in a long format - generates a list in full mode format |
ps -e -l |
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stops a process from running using its PID - used to kill a stubborn process that won't die |
kill - -9 ex: pkill -9 <PID> |
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stops a process from running using its process name - used to kill a stubborn process that won't die - Used to immediately re-spawn a process to effect configuration changes. |
pkill - -9 -HUP |
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maintains a history file of all successfully run commands by a particular user |
history |
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determines file type |
file |
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prints the strings of printable characters in a file. |
strings <filename> |
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displays the user who is logged in |
whoami |
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displays user login information including login name, timer, terminal, and more |
who |
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displays information about the user logged in and what they are doing |
w |
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prints or sets the system date and/or time - sets the date to the date and time provided |
date -s |
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Tape archive utility used to archive files to tape or disk - create - list table contents of tar file - extract, must be in target directory to extract - verbose, list each file as tar reads/writes - read/write to or from file |
tar c t x v f |
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compresses files and saves the with a .gz file extension |
gzip |
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this utility decompresses a file which was compressed with gzip |
gunzip |
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this utility compresses files and saves them with a .bz2 file extension |
bzip2 |
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this utility decompresses a file which was compressed with bzip2 |
bunzip2 |
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schedules a job/process for a one-time execution |
at <schedule time> |
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list users pending jobs |
atq |
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deletes user's jobs identified by job number |
atrm |
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schedules periodic jobs -edit -list |
crontab -e -l |
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permission sets for files and directories are set with what command |
chmod - r read (4) - w write (2) - x execute (1) |