Linux File Management and Viewing
File and Directory management
| apropos | | Search the whatis database for files containing specific strings. |
| bdflush | | Kernel daemon that saves dirty buffers in memory to the disk. |
| cd | | Change the current directory. With no arguments "cd" changes to the users home directory. |
| chmod | | chmod <specification> <filename> - Effect: Change the file permissions.
| Ex: chmod 751 myfile | | Effect: change the file permission to rwx for owner, re for group |
| Ex: chmod go=+r myfile | | Effect: Add read permission for the owner and the group |
character meanings u-user, g-group, o-other, + add permission, - remove, r-read, w-write,x-exe
| Ex: chmod a +rwx myfile | | Effect: Allow all users to read, write or execute myfile |
| Ex: chmod go -r myfile | | Effect: Remove read permission from the group and others |
chmod +s myfile - Setuid bit on the file which allows the program to run with user or group privileges of the file.
chmod {a,u,g,o}{+,-}{r,w,x} (filenames) - The syntax of the chmod command.
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| chown | | chown <owner1> <filename> Effect: Change ownership of a file to owner1. |
| chgrp | | chgrp <group1> <filename> Effect: Change group. |
| cksum | | Perform a checksum and count bytes in a file. |
| cp | | cp <source> <destination> Copy a file from one location to another. |
| dd | | Convert and copy a file formatting according to the options. Disk or data duplication. |
| dir | | List directory contents. |
| dircolors | | Set colors up for ls. |
| file | | Determines file type. Also can tell type of library (a.out or ELF). |
| find | | Ex: find $Home –name readme Print search for readme starting at home and output full path.
How to find files quickly using the find command:
Ex: find ~ -name report3 –print
- "~" = Search starting at the home directory and proceed through all its subdirectories
- "-name report3" = Search for a file named report3
- "-print" = Output the full path to that file
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| install | | Copy multiple files and set attributes. |
| ln | | Make links between files. |
| locate | | File locating program that uses the slocate database. |
| losetup | | Loopback device setup. |
| ls | | List files. Option -a, lists all, see man page "man ls"
Ex: "ls Docum Projects/Linux" - The contents of the directories Docum and Projects/Linux are listed.
To list the contents of every subdirectory using the ls command:
- Change to your home directory.
- Type: ls -R
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| mkdir | | Make a directory. |
| mknod | | Make a block or character special file. |
| mktemp | | Make temporary filename. |
| mv | | Move or rename a file. Syntax: mv <source> <destination> Ex: mv filename directoryname/newfilename |
| pathchk | | Check whether filenames are valid or portable. |
| pwd | | Print or list the working directory with full path (present working directory). |
| rm | | Ex: "rm .*" - Effect: Delete system files (Remove files) –i is interactive option. |
| rmdir | | rmdir <directory> - Remove a directory. The directory must be empty. |
| slocate | | Provides a secure way to index files and search for them. It builds a database of files on the system. |
| stat(1u) | | Used to print out inode information on a file. |
| sum | | Checksum and count the blocks in a file. |
| test | | Check file types and compare values. |
| touch | | Change file timestamps to the current time. Make the file if it doesn't exist. |
| update | | Kernel daemon to flush dirty buffers back to disk. |
| vdir | | List directory contents. |
| whatis | | Search the whatis database for complete words. |
| wheris | | Locate the binary, source and man page files for a command. |
| which | | Show full path of commands where given commands reside. |
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| ar | | Create modify and extract from archives. |
| bunzip2 | | Newer file decompression program. |
| bzcat | | Decompress files to stdout. |
| bzip2 | | Newer file compression program. |
| bzip2recover | | Recovers data from damaged bzip2 files. |
| compress | | Compress data. |
| cpio | | Can store files on tapes. to/from archives. |
| dump | | Reads the filesystem directly. |
| gunzip | | unzip <file> - unzip a gz file. |
| gzexe | | Compress executable files in place. |
| gzip | | gzip <file> - zip a file to a gz file. |
| mt | | Control magnetic tape drive operation. |
| tar | | Can store files on tapes.
Usage: tar cvf <destination> <files/directories> - Archive copy groups of files
Ex: tar /dev/fdo temp Effect: Copy temp to drive A: |
| uncompress | | Expand data. |
| unzip | | unzip <file> - unzip a zip file. Files ending in ".gz" or ".zip" are compressed. |
| zcat | | Used to restore compressed files. |
| zcmp | | Compare compressed files. |
| zdiff | | Compare compressed files. |
| zforce | | Force a .gz extension on all gzip files. |
| zgrep | | Search possibly compressed files for a regular expression. |
| zmore | | File filter for crt viewing of compressed text. |
| znew | | Recompress .z files to .gz files. |
| zip | | zip <file> - make a zip file. |
| basename | | Strip directory and suffix information from filenames. |
| cat | | Ex: cat < filename --- Effect: put keyboard input into the file. CTRL-D to exit (end). |
| cmp | | Compare two files. |
| colrm | | Remove columns from a file. |
| column | | Columnate lists. |
| comm | | Ex: comm file1 file2 --- Effect compare the contents of file1 and file2 produces 3 columns of output. Lines in the first file, lines in second file, lines in both files. |
| csplit | | Split a file into sections determined by context lines. |
| cut | | Remove sections from each line of files. |
| diff | | Show the differences between files. Ex: diff file1 file2 |
| diff3 | | Find differences between 3 files. |
| dirname | | Strip the non-directory suffix from a filename. |
| echo | | Display a line of text. |
| egrep | | Similar to grep -E, compatible with UNIX egrep. |
| expand | | Convert tabs to spaces. |
| expr | | Evaluate expressions. |
| false | | Do nothing. Exit with a status indicating failure. |
| fgrep | | Same as grep -F. |
| fold | | Wrap each input line to fit in specified width. |
| join | | Join lines of two files in a common field. |
| grep | | grep pattern filename.
Ex: grep " R " --- Effect: Search for R with a space on each side
Ex: ls –a |grep R --- Effect: List all files with an R in them or their info listing. |
| hexdump | | asc, decimal, hex, octal dump. |
| logname | | Print user's login name. |
| look | | Display lines beginning with a given string. |
| mkfifo | | Create named pipes with the given names. |
| nl | | Write each file to standard output with line numbers added. |
| od | | Dump files in octal and other formats. |
| patch | | Apply a diff file to an original. |
| paste | | Combines from 2 or more files. Ex: paste file1 file 2 |
| printf | | Print and format data. |
| rev | | Reverses lines in a file. |
| script | | Make a typescript of a terminal session. |
| sdiff | | Find differences between 2 files and merge interactively. |
| sed | | A stream editor. Used to perform transformations on an input stream. |
| sleep | | Delay for a specified amount ot time. |
| sort | | Sort a file alphabetically. |
| split | | Split a file into pieces. |
| strings | | Print the strings of printable characters in files. |
| tac | | Concatenate and print files in reverse. |
| tee | | Read from standard input and write to standard output and files. |
| tr | | Translate or delete characters. |
| true | | Do nothing. Exit with a status indicating success. |
| tsort | | Perform topological sort. |
| ul | | Do underlining. |
| unexpand | | Convert tabs to spaces. |
| uniq | | Remove duplicate lines from a sorted file. |
| uudecode | | Used to transform files encoded by uuencode into their original form. |
| uuencode | | Encode a binary file to be sent over a medium that doesn't support non-ASC data. |
| wc | | Count lines, words, characters in a file. Ex: wc filename. |
| xargs | | Build and execute command lines from standard input. |
| yes | | Output the string "y" until killed. |