Filesystem Informational Text Filtering / Mutative bzip2 [opts] [filepattern] ·bzip2 Compression (better) cat [opts] [filepattern] ·Print file contents on STOUT average [opts] [fileargs] ·Print the average of all numbers encountered cd [-] [directory] ·Change directory -E :Display a $ at the end of each line awk [opts] [exp] ·pattern scanning and processing language - :Change to the previous directory you were in -T :Show tabs as ^I -F<fs> :Set the field separator to <fs> chmod [opts] <mode> <filepattern> ·Change permissions -v :Show non-printing characters Ex: cat access_log | awk {‘print $1’} (prints hostnames) -R :Change permissions recursively date [opts] ·Print or set the system date and time Do a ‘man awk’ for more information and examples STRING STRING comm [opts] [file1] [file2] ·Compare two sorted files chown [opts] <user>[.group] <file> ·Change ownership --date= :display time described by STRING STRING -R :Change ownership recursively --set= :set time described by -1 :Suppress lines unique to left file -2 :Suppress lines unique to right file cp opts from to ·Copy files and directories dmesg [opts] ·Print or control the kernel ring buffer [ ] < > < > -3 :Supress lines unique to both files -i :Interactive mode. Prompt before overwriting -c :Clear the contents of the ring buffer csplit [opts] [file] [pattern] ·Split a file on context -p :Preserve file permissions and ownership file [opts] [filepattern] ·Determine the file type prefix prefix -R :Copy directories recursively -z :Try to look inside compressed files -f :Use instead of xx in output filenames -n <digits> :Use <digits> number of digits instead of 2 df [opts] [device name] ·Print filesystem usage info finger [opts] [userpattern] ·Show info about system users -m :Match the exact username specified -z :Remove empty output files -a :Show all filesystems Ex: csplit mailspoolfile "/^From /" {*} -h :Human readable format/Quantify byte information free [opts] ·Display free and used memory in the system cut [opts] [filepattern] ·Remove sections from each line -i :Show inode usage info -b :Display the information in bytes -c range :Output only the characters in range du [opts] [pattern] ·Show space usage on files and dirs hexdump opts ·Show all the characters of a file [ ] Ex: cut –c 1-80 file (truncate lines at 80 characters) -c :Produce a grand total for all arguments -c :Display the input offset in hexidecimal diff [opts] [file1] [file2] ·Differentiate two files -h :Human readable format/Quantify byte information last opts username ·Show last system logins for users [ ] [ ] Ex: diff program-old.c program.c > program.patch -s :Summarize. Only show a total for each argument -num :Show last num of sessions echo [opts] [string] ·Print a line of text find <path> [opts] ·Search for a file -a :Display the hostname in the last column -d :Translates IP numbers to their hostname -e :Enable interpretation of backslashed sequences -f <file> :Use file as last log -n :Don’t automatically insert a newline character Learning find, once and for all! fold [opts] [files] ·Wrap each line to a specified width Find all non-world readable html/htm files and change less [opts] [filepattern] ·View a file a page at a time -i :Do case insensitive searching -s :Break at spaces instead of in the middle of a word. their user ownership to fred using chmod: WIDTH WIDTH -S :Don’t wrap long lines -w < > :Use < > columns rather than 80 find / -type f –name ‘*.html’ -o -name '*.htm' -a +[less commands] :Pass initial commands to less grep [opts] [pattern] [file] ·Print lines matching pattern –perms –644 -exec chown fred {} \; lsof [opts] [names] ·List all open files -B <num> :Print <num> lines of leading context on matches -C <num> :Print <num> lines of trailing context on matches gzip [opts] <filepattern> ·Compress a file or files -E :Interpret pattern as an extended regular expression -1..9 : Set compression level. 9=highest, 1=lowest Try these useful tasks with lsof -i :Do case insensitve matching -d :Decompress file. Same as the gunzip command When the CD-ROM is “busy”: lsof /dev/cdrom -l :Just print the files that match the pattern -v :List the statistics for a compressed file Programs using audio: lsof /dev/dsp -r :Read all files under each directory recursively ln [opts] <tofile> <linkfile> ·Create a sym/hard link -v :Print the lines that don’t match pattern lsof -i 4 -a -s :Create a symbolic link between files (alias name) List open ipv4 network files: head [opts] [file] ·Print the first part of a file -f :Force creation, even if the link file exists -n num :Print the first num lines instead of the first 10 man [opts] [section] <manpage> ·View software manual pages ls [opts] [pattern] ·List file and directory entries numsum [opts] [filepattern] ·Print the sum of a group of numbers -a :View all available manual pages for name Ex: cat numbers.txt | numsum (Add up all numbers in a file) -a :List all files including ones that start with '.' Ex: 'man ls' or 'man -a nice' or 'man 5 crontab' numgrep </numpattern/> [filepattern] ·Print lines matching numpattern -d :List directories themselves, not their contents md5sum [opts] [filepattern] ·Show the uniqueness of files Ex: cat numbers.txt | numgrep /2..100/ (Print numbers from 2 to 100) -l :Long list. Shows permissions and modified time nl [opts] [file] ·Number the lines of a file -r :Recusively list files in directories -c :Check MD5 sums of files against md5sum listfile paste [opts] [files] ·Merge lines of files horizontally -S :Sort output by file size ps [opts] ·Show what processes are running on the system -h :Human readable format/Quantify byte information a :Select all processes on a terminal patch [opts] [patchfile] ·Patch a file using a diff file -X :Sort by filename extension u :Display user oriented format. More columns sed [expression] [file] ·Stream editor -1 :Print output files one per line x :Select processes without a controlling TTY Ex: cat file | sed ‘s/frompattern/topattern/’ > output --time=atime :Show last access timestamp for file w :Show an extra line of process entry per w specified sort [opts] [file] ·Sort lines of text files mkdir [opts] <dirname> ·Make a new directory Ex: ps auxwww =Displays all process information on system -n :Compare according to string numerical value -p :Create parent directories if they don’t exist quota [opts] [user] ·Display disk usage and limits -r :Reverse the result of comparisons -v :Display filesystems where no quota is set mv [-i] <frompattern> <tofile> ·Move/Rename a file split [opts] [file] ·Split a file into pieces random </numpattern/> ·Print out a random number from numpattern -i :Interactive move (Prompt before moving files) -l <num> :Put <num> lines per output file Ex: random /500..1000/ (print a random number between 500 and 1000) opts filepattern ·Remove a file opts file ·Print the last lines of a file rm [ ] < > slocate [opts] [pattern] ·Locate pattern in file index db tail [ ] [ ] -f :Force removal (Don’t ask if it’s ok to remove) -i : Case insensitive search -f :Output appended data as the file grows num> num> -i :Interactive remove (Ask before removing each file) -r : Search the database using POSIX regular expressions -n < :Print last < lines of instead of the last 10 -r :Recusively delete directories an their contents opts file ·Send current output stream to file time [opts] [command] ·Show resource usage for a command tee [ ] [ ] shred [opts] <filepattern> ·Delete file data securely -a :Append to the given file instead of overwriting top [opts] ·Display top CPU processes every X seconds -n :Number of pattern iterations to run (default 25) tr [opts] <set1> [set2] ·Translate char. from set1 to set2 -d sec :Set the delay to sec seconds before refreshing -u :Truncate and remove the file after overwriting Ex: cat index.html | tr A-Z a-z > index-new.html -z :Add a final overwrite with zeros to hide shreding umask [opts] [mode] ·Set the default file permissions uniq [opts] [input] [output] ·Remove duplicate lines tar [opts] [tarfile] [pattern] ·Create an archive -S :Show current symbolic umask -c :Prefix lines with number of occurances uname opts ·Show OS and system information c :Create mode. Create a tar archive [ ] -d :Only print duplicated lines x :Extract mode. Untar archive contents -a :Show everything -u :Only print unique lines t :List mode. List the contents of the archive uptime ·Show system uptime and load -w <n> :Check no more than <n> characters in lines f :Specify a tarfile to use w [opts] [user] ·Show who is logged in/what they are doing wc [opts] [file] ·Print the number of lines in files, etc. v :Verbose mode. Show files being added or untared command ·Locate the related files for a command z,j :De/compress. Send i/o through gzip(z) or bzip2(j) whereis [ ] -m :Print the character count command Show full path to the specified command -l :Print the line count touch [opts] <pattern> ·Update the timestamp on a file which [ ] · who [opts] [args] ·Show who is logged in -w :Print the word count -t :Specify a timestamp to use instead of current time -L :Print the length of the longest line Network Bash Shell Admin ifconfig [devicename] [action] [options] > ·Send STDOUT to a file. overwrite/create a file adduser [opts] <username> ·Add a user to the local system ipchains [opts] ·Manip. ipchains firewall(kernel 2.2+) Ex: ls –l > list-of-files.txt -d <dir> : Set the home directory for the user to dir iptables [opts] ·Manip. iptables firewall(kernel 2.4+) >> ·Send STDOUT to a file, appending to te end of the file -g <group> : Set the primary group for the user to group group