Basic Linux. Advanced NDC Training Course

Transcription

1 Advanced NDC Training Course Basic Linux Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization Provisional Technical Secretariat Vienna International Centre P.O. Box 1200 A-1400 Vienna AUSTRIA IDC Page 1

2 Introduction Files, Directories, Processes Kernel, Shell and Applications (programs) Pattern Matching Redirection and Pipelines Page 2

3 Introduction Scope Basic concepts and terminology; how to get started. Familiarity Problem I have been using SunOS, Solaris and Linux for ~ 20 years. Further Information The man pages, info and Google. Page 3

4 Files and Processes - Everything is a file or a process! Files Files contain blocks of arbitrary data. Are usually persistent (e.g. written to disk) and available to processes. Protected by permissions and may be executable (more later). They can be created, copied, renamed, moved, deleted. Directories are a special kind of file they contain other files. Directories are organised in a tree structure. Navigate using cd (pwd gives current directory). There are some other types of special files, but they are rarely used. Page 4

5 Directory Structure Alternative Representations This type is more common Page 5

6 File Names Some Guidelines Filename are CaseSeNSitiVe Suffix usually gives a clue as to the content of the file; some applications expect a certain extension They can normally be up to 255 characters Very long filenames can cause some problems; filename completion saves typing! It is possible to use almost any character in a Unix filename BUT doing this normally results in complications Avoid the following types of filenames (even though they are valid) Report For 2008.Txt ( embedded spaces, unusual capitalisation of Txt ) Terms&Conditions.txt ( embedded '&' character ) Sily*File.txt (embedded wildcard character) -WithDollar$.txt (leading - (dash or minus sign) and embedded '$' character) ThisHas^G^GControlCharsInIt.txt (embedded control characters) [ Check: ls. od -t a ] ls (name of an existing Unix command) -ls (leading '-' (minus) sign) Page 6

7 Files and Processes - Everything is a file or a process! Process An instance of a computer program being executed. The execution of the instructions in the source code. Many processes, owned by different users, can run at once. Linux is a multi-tasking, multi-user operating system. Can be run in the foreground or the background Uniquely identified by a process id. Find processes using ps (or top or jobs) command (kill to interact). Has a stdin, stdout and stderr associated with it. Normally associated with the keyboard and screen respectively Can be re-directed or piped (more later) Returns an exit code to the shell Page 7

8 Shell The user interface User inputs text for a command line interpreter to execute. Linux provides user-selectable shells, e.g. sh, bash, ksh, csh, tcsh, scsh etc. etc. etc. Every Linux system has a shell compatible with sh Provides builtin functions: wildcards, history, filename completion etc. Graphical User Interfaces (GUI) are essentially graphical shells Often runs shell commands directly under the hood Command line interface provides powerful, flexible, modular control Cannot do everything in a GUI sometimes you need the CLI! The shell is both: command line interpreter (CLI) scripting language very good at automating repetitive tasks But there are better choices: perl, python etc. Page 8

9 Commands, flags and arguments There is always a command ; it is always the first word Examples: cat, ls, w, whoami, uptime, reboot Words are separated by whitespace (space or tab) Examples: cat file1.txt file2.txt file3.txt There may be zero or more command line arguments (CLA) Flags (or options ) are used to modify default behaviour There are very many flags; they normally start with - (or -- ); they are case sensitive. Several flags can often be combined within a single - Examples: sort r file.txt, ls l -R /tmp, ls lartr /tmp, date u Lines can be continued using \ as the last character of the line The following often need special care: <space> *? [ ] { } $ Page 9

10 Commands, flags and arguments ls Page 10

11 Commands, flags and arguments ls l Page 11

12 Commands, flags and arguments ls l test.c Page 12

13 Commands, flags and arguments ls l a r -t test.c Page 13

14 Commands, flags and arguments ls l a r -t test.c ls lart test.c ls lart test.c main.c ls lart test.c main.c *.c *.h *.[ch] Multiple, combined flags Multiple arguments Wildcards Page 14

15 Pattern Matching ( globbing ) Convenience function provided by all shells Two main operators: * and? (except leading '.') Other operators: '[' and ']' (also '{' and '}') Allows zero or more file (or directory) names to be matched Examples: stderr stdout wclist README dirlist.cb.cshrc.bash_profile ls * ---> stderr stdout wclist README dirlist ls -a * ---> {all files:incl. dot files + dirs } ls -a *.* ---> ls: *.* : No such file or directory ls -l.[a-z] ---> ls:.[a-z] : No such file or directory ls.[a-z]* --->.cb.cshrc.bash_profile ls readme ---> ls: readme : No such file or directory ls.* ; ls -d.* --->?? Page 15

16 Redirection (1) Standard I/O interface for all Linux commands: stdin, stdout, stderr Details are shell-specific Bash supports much better redirection capabilities than tcsh Redirection (>, >&, >>) Input can be re-directed from files (or here documents) Output can be re-directed to files (or /dev/null ) Normal and error output can be independently re-directed ls -l *.c > Source_files.list ls -l *.c >> Source_files.list ls -l *.c >& Source_files.list # tcsh # tcsh # tcsh ( ls -l *.c >./out ) >&./err # easier in bash Page 16

17 Redirection (2) INPUT can be re-directed from files (or here documents) wc l < application_log.txt # Not the same as wc l application_log.txt wc l << EndOfDocument Line one Line Two Third Line of text Final_LINE EndOfDocument Page 17

18 Redirection (2) INPUT can be re-directed from files (or here documents) wc l < application_log.txt # Not the same as wc l application_log.txt wc l << EndOfDocument # quotes are useful, not mandatory, but must match Line one Line Two Third Line of text Final_LINE EndOfDocument # the terminator string must be at the start of line Page 18

19 Pipelines Pipelines ( ): Allows chaining of stdout from one process to stdin of the next Linux is built from modular applications Lots of applications, each performing a small task; read stdin, write stdout Pipelines are the key to harnessing the full power of Linux Well worth the time to become familiar with pipelining applications together Widely used and very powerful technique Pipelines can be simple ls -l *.c sort -nr k 5,5 > Source_files.list Page 19

20 Pipelines Pipelines ( ): Allows chaining of stdout from one process to stdin of the next Linux is built from modular applications Lots of applications, each performing a small task; read stdin, write stdout Pipelines are the key to harnessing the full power of Linux Well worth the time to become familiar with pipelining applications together Widely used and very powerful technique Pipelines can be simple, or very complex ls -l *.c sort -nr k 5,5 > Source_files.list ls l *.c sort nr k 5,5 grep v _time_ \ sed e s/\.c$/.cpp/g tr a-z A-Z \ cut c 28- awk {printf %s\t%s\n,$5,$1} Page 20

21 Pipeline stdin, stdout and stderr The stderr always goes to the terminal Still see errors when redirecting stdout Can be directed to separate files Easy in bash, difficult in csh! Page 21

22 Getting Help the man page export PAGER= less setenv PAGER less Page 22

23 Getting Help the man page Page 23

24 Getting Help the man page Page 24

25 Getting Help info not for the faint-hearted! Page 25

26 Getting Help info not for the faint-hearted! C-x 0 = <Control> + x + zero Page 26

27 Getting Help Google Page 27

28 Page 28 Thank you

29 Advanced Linux Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization Provisional Technical Secretariat Vienna International Centre P.O. Box 1200 A-1400 Vienna AUSTRIA Page 29

30 Introduction Kernel, Shell and Applications (programs) Environment Permissions and Shellscripts Cron jobs Useful Commands Page 30

31 What do you know already? (1) 1. ls ; LS 2. ls -lartr ~/dd ; ls -a -l -R -r -t ~/dd ; ls -lrtr ~/dd 3. ls *.c > listing.txt 4. ls -l grep txt less 5. lp -d printer_name Resume.txt 6. cd ; cd ~ ; cd $HOME ; cd ${HOME} 7. man find 8. ed R.txt ; vi R.txt ; emacs R.txt ; gedit R.txt ; nedit R.txt 9. cp -prf./foo./bar ; mv./foo./bar Page 31

32 What do you know already? (2) 1. ls -l grep txt 1> /tmp/misc/text_files.txt 2>&1 2. echo "Today is `date -u`" 3. find. -name '*.c' -print 4. find ${HOME} -type f -name \*.c \ -exec grep -iv "core " {} \; 5. find ${HOME} -type f -name \*.c \ -exec grep -iv "core" {} /dev/null \; 6. cd `imspar RELBIN` && tar cf -. gzip -c -1 \ scp auto@idclx006 cat ">" /local/foo/geotool.tar.gz Page 32

33 Linux commands and terms Page 33

34 Kernel, Shell and Applications (programs) Kernel Controls resources (CPU, memory, I/O) Use uname command to see kernel name and other information Shell Passes commands to the kernel for execution, then waits for the command to complete and prompts for new command. Has some time-saving features (completion, wildcards, history) Many variations (sh, bash, ksh, csh, tcsh). You will use tcsh. Application Software (programs) Built-in commands such as ls, rm or more complex, custom-written code such as GIMP, geotool or the CD Tools Page 34

35 Graphical User Interface (GUI) Page 35

36 Graphical User Interface (GUI) Page 36

37 Graphical User Interface (GUI) It's a command line under the hood! Page 37

38 Kernel, Shell and Applications (schematic) Page 38

39 Running Commands Commands are entered at the shell prompt followed by zero or more command line arguments (CLAs) Many commands that can be given file names as command line arguments read stdin and write to stdout if no CLAs are given Commands can be run in the foreground or in the background running in the background allows the terminal to be used for other commands Commands that require input from stdin should not be run in the background! gedit & (OK, X application) but vi test.c & ( Problem: Suspended (tty output) ) Common sequences of commands can be put into a test file which is made executable (a shellscript ) Page 39

40 Permissions All files (incl. directories etc.) have permissions associated with them All users have a user id (name) and a primary group Files created by a user are owned by that user and primary group Permissions are controlled at three levels: user, group and other (ugo) The command ls displays permissions, chmod is used to change them Permissions on a file control who can read, write and execute it (rwx) Directories require read and execute permission! Sequences of commands entered into a text file become a shellscript (or simply a script ). Just make the file executable! the start.cdtool script is one such example (to start/restart the CD Tools) Examples vi my_script.sh; chmod u+x my_script.sh;./my_script.sh Page 40

41 A Simple Bash Shell Script #!/bin/bash # Using printf to format error messages... EXIT_SUCCESS=0 EXIT_ERROR=1 var="/non/existent/directory" echo -n "Enter directory to cd to: " read # goes to default $REPLY if [! -z "$REPLY" ]; then var=$reply fi fatal_error() { } # Formats positional params passed, and sends them to stderr. # Wrap the basic error with FATAL. Finish with info about exit status. printf "\nfatal: " >&2 printf "$@" >&2 printf "\nexiting with status=%d.\n\n" $EXIT_ERROR >&2 exit $EXIT_ERROR # Generate a formatted error message if the cd fails cd $var 2>/dev/null fatal_error $"Can't change directory (cd) to %s." "$var" exit $EXIT_SUCCESS Page 41

42 Cron Jobs Cron allows commands to run automatically at given times Extensively used to produce daily reports (e.g. squal) Frequency can be adjusted to one minute resolution Not all users are allowed to run cron jobs Timing and command information modified using crontab command Commands are executed using the Bourne shell (sh) this frequently catches users out if their environment is not configured! Any output to stdout and stderr is ed back to the user it is normal to write output to a logfile and redirect stdout and stderr to /dev/null Example: 5,35 * * * * ( env `cat cron.shenv`./bin/lasid_snapshot > /dev/null 2>&1 ) Page 42

43 Useful Commands - General Points Commands are case-sensitive typing./boring_tasks is not the same as typing./boring_tasks The PATH environment is used to find commands that are not preceded by an absolute pathname be careful with. in the PATH environment. It is often safer to explicitly specify./program Commands can be separated by: ; & && ; = run the commands sequentially & = run the command in the background in a sub-shell = pipe the output of this command to the input of the next command && = only run the second command if the first command finished successfully = only run the second command of the first command exited with non-zero status Sequences of commands can be run as a shellscript simply edit a text file, then make it executable, using chmod! Page 43

44 Redirection send output to a file. A process has three standard input-output channels associated with it: STDIN Usually the keyboard. This is file descriptor 0 (zero). STDOUT Usually the screen. File descriptor 1 (one). STDERR Always the screen. File descriptor 2 (two). Most Unix commands Read input from STDIN Write output to STDOUT Report errors to STDERR Any of these three channels can be redirected from/to a file They can also be piped to other commands (more later) Input redirection = Taking STDIN from a file Output redirection = Sending STDOUT to a file. Note: this does not affect the STDERR, which still goes to the screen! This is a very common technique for separating errors from lots of routine output. One special target for redirection is /dev/null (for input and/or output) Page 44

45 Redirection (2) Many Unix commands read from STDIN if no filename is given grep test... will search for the string test - from STDIN (usually the keyboard) If the program appears to have hung, it may actually be waiting for input from the keyboard! Similarly, they write to STDOUT if no filename is given You may get lots of output to the screen! It is sometimes necessary to use the special filename - (minus) This can represent STDIN or STDOUT, depending on the context e.g. tar cf -. ( cd /tmp ; tar xf - ) [ first '-'=STDOUT, second '-'=STDIN ] There are special operators to indicate redirections: Output: > = Redirect the STDOUT [e.g. ls > stdout.txt ]. Use >> to append to existing file. Input: < = Redirect the STDIN [e.g. cat < stdin.txt ] Output (stderr too): This depends on the shell being used... ls >& /stdout+stderr.txt (csh) OR ls > stdout+stderr.txt 2>&1 (bash) The backtics operator ` redirects the stdout sqlplus `imspar PUBLICDB` ^D (control key + 'd') to send end of file from the keyboard Page 45

46 Redirection A complex bash shell example Note: you cannot do this with the csh! Source: Page 46

47 Environment All commands run with a certain environment This is usually set up when you login (e.g. ~/.bash_profile, ~/.tcshrc) Content of the environment can be displayed using printenv Details of displaying and setting the environment are shell-specific bash: export PATH= /usr/bin:/dvl/software/shi/rel/bin:. tcsh: setenv PATH /usr/bin:/dvl/software/shi/rel/bin:. Changes to environment often require changes to be sourced bash:. ~/.bash_profile tcsh: source ~/.tcshrc [ ~ = Home directory ] Non-interactive processes normally use the Bourne shell (sh) this catches many people out (e.g. commands run interactively but not as cron jobs) Important environment variables are: PATH, LD_LIBRARY_PATH, GEOTOOL_HOME, PRINTER, DISPLAY, EDITOR Page 47

48 Permissions Page 48

49 Logging in to remote systems using ssh Set up ssh keys to allow logins without passwords ssh-keygen b 1024 t rsa Give it a passphrase of reasonable length (make it memorable!) Default location is ~/.ssh (id_rsa and id_rsa.pub) Login to remote machine using ssh (or scp) You will still need the password this time cat id_rsa.pub >> ~/.ssh/authorized_keys Logout of remote machine Next login should be without password Cache your keys for one login session using ssh-add You will be prompted to enter your passphrase Page 49

50 Using ssh and scp If ssh keys are not set up you will be prompted for password each time! General syntax: ssh [-X] scp local_filename machine:/path/on/remote/machine/remote_filename scp /path/to/local_filename Wildcards in remote file names need to be escaped or quoted scp local_filename*.txt scp machine:/path/on/remote/machine/remote*.txt./ Page 50

51 Page 51 Thank you

52 Unix and Linux Unix was developed in the 1960's; the Linux kernel in 1991 Stable, multi-tasking, multi-user operating system Available for servers, desktops and laptops Several different flavours : Solaris, GNU/Linux, MacOS-X Some commands have Graphical User Interface (GUI) but many commands are available only from the command line! many GUIs simply call command line programs under the hood Three basic elements: Kernel allocates time and memory, interacts with filestore, deals with system calls. Shell command line interpreter between the user and the kernel (e.g. sh, ksh, csh, tcsh, bash etc.) Applications (programs) commands such as GIMP, nautilus, ls, rm, cp, cd, vi etc. Everything is either a file or a process Files contain data. Processes are running programs. Directories are arranged in tree structures, with / (root) at the top Page 52

53 Process State Diagram and Transitions Created (fork, exec) Scheduled Running Blocked (waiting for resource) Swapped out (if not enough physical memory) Page 53

54 Useful Commands Simple Commands Files and Directories pwd, ls -aalhrrt, cd, du -shk, cp -ipr, rm -irf, mv -I Users and groups id, groups, w, last, finger username Processes top, ps -fu {USER}, ps -ef, kill -{SIG} pid, strace -p pid Environment printenv,., env, echo ${ENV_NAME} Utilities vi file, emacs file grep -iv, egrep -iv, sort -urnk, wc -clw, md5sum file find {commands} ---> this one is so powerful you could write a book about it! chmod mode file, ping IP_Address, nslookup domain_name, hostname Page 54

55 Pipelines Pipelines provide communication between processes Both processes must be on one computer The communication is unidirectional ls sort Page 55

56 Pipelines Can be arbitrarily long You can pipeline together as many processes as necessary -rw-rw-r-- 1 hampton smd Nov 5 17:45 GIMP-GUI.png -rw-rw-r-- 1 hampton smd Nov 5 20:08 Redirection-Oreilly.gif -rw-rw-r-- 1 hampton smd Nov 5 20:13 Redirection-after operations.gif -rw-rw-r-- 1 hampton smd Nov 5 20:13 Redirection-after operations.gif -rw-rw-r-- 1 hampton smd Nov 5 20:11 Redirection-using-dummy-stream3.gif -rw-rw-r-- 1 hampton smd Nov 5 20:57 Unix-pipeline-wikicommons.png -rw-rw-r-- 1 hampton smd Nov 5 17:41 cd-creator-gui-under-the-hood.png [...] # A 10-component pipeline.. ls -l head grep -v "^total" awk '{print $3,$5,$9}' \ sort -n -k 2,2 tr '[a-l]' '[A-L]' grep ' CD-' \ cut -c 5-11 tail sort less ton 128 ton 324 (END) Page 56

57 Pattern Matching Examples Which files would be selected by the following commands? ls drwxrwxr-x 3 hampton smd 4096 Nov 5 21:24. drwxrwxr-x 3 hampton smd 4096 Nov 5 21:24.. -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.a -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.bashrc -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.cshrc -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.file1 -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.gimp drwxrwxr-x 2 hampton smd 4096 Nov 5 21:25.l -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.ll -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 File1 -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 a -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 abc -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 b -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 bb -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 bbb -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 c -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 cba -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 cbc -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 file1 -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 l -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 m Page 57

58 Pattern Matching Examples Which files would be selected by the following commands? ls drwxrwxr-x 3 hampton smd 4096 Nov 5 21:24. drwxrwxr-x 3 hampton smd 4096 Nov 5 21:24.. -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.a -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.bashrc -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.cshrc -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.file1 -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.gimp drwxrwxr-x 2 hampton smd 4096 Nov 5 21:25.l -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.ll -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 File1 -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 a -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 abc -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 b -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 bb -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 bbb -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 c -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 cba -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 cbc -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 file1 -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 l -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 m Page 58

59 Pattern Matching Examples Which files would be selected by the following commands? ls -a drwxrwxr-x 3 hampton smd 4096 Nov 5 21:24. drwxrwxr-x 3 hampton smd 4096 Nov 5 21:24.. -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.a -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.bashrc -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.cshrc -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.file1 -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.gimp drwxrwxr-x 2 hampton smd 4096 Nov 5 21:25.l -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.ll -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 File1 -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 a -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 abc -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 b -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 bb -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 bbb -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 c -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 cba -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 cbc -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 file1 -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 l -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 m Page 59

60 Pattern Matching Examples Which files would be selected by the following commands? ls -a drwxrwxr-x 3 hampton smd 4096 Nov 5 21:24. drwxrwxr-x 3 hampton smd 4096 Nov 5 21:24.. -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.a -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.bashrc -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.cshrc -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.file1 -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.gimp drwxrwxr-x 2 hampton smd 4096 Nov 5 21:25.l -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.ll -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 File1 -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 a -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 abc -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 b -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 bb -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 bbb -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 c -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 cba -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 cbc -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 file1 -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 l -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 m Page 60

61 Pattern Matching Examples Which files would be selected by the following commands? ls.[a-z]* drwxrwxr-x 3 hampton smd 4096 Nov 5 21:24. drwxrwxr-x 3 hampton smd 4096 Nov 5 21:24.. -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.a -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.bashrc -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.cshrc -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.file1 -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.gimp drwxrwxr-x 2 hampton smd 4096 Nov 5 21:25.l -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.ll -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 File1 -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 a -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 abc -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 b -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 bb -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 bbb -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 c -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 cba -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 cbc -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 file1 -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 l -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22 m Page 61

62 Pattern Matching Examples Which files would be selected by the following commands? ls.[a-z]*.a.bashrc.cshrc.file1.gimp.ll.l: # Note: this is a directory listing Page 62

63 Pattern Matching Examples Which files would be selected by the following commands? ls -a.[a-z]*.a.bashrc.cshrc.file1.gimp.ll.l: # Note: this is a directory listing....hidden_file Page 63

64 Pattern Matching Examples Which files would be selected by the following commands? ls -la.[a-z]* -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.a -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.bashrc -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.cshrc -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.file1 -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.gimp -rw-rw-r-- 1 hampton smd 0 Nov 5 21:22.ll.l: drwxrwxr-x 2 hampton smd 4096 Nov 5 21:25. drwxrwxr-x 3 hampton smd 4096 Nov 5 21:24.. -rw-rw-r-- 1 hampton smd 0 Nov 5 21:25.hidden_file Page 64

65 Pattern Matching Examples Which files would be selected by the following commands? ls -a.*.a.bashrc.cshrc.file1.gimp.ll.: # (current) directory....a.bashrc.cshrc.file1.gimp.l.ll File1 a abc b bb bbb c cba cbc file1 l m..: # (parent) directory one level above this one!... foo.l: # named subdirectory....hidden_file Page 65

66 Wildcards Some Practical Examples....bash_profile.cb.cshrc README dirlist stderr stdout wclist bash-3.1$ ls * bash-3.1$ ls -a * bash-3.1$ ls -a *.* bash-3.1$ ls -l.[a-z] bash-3.1$ ls.[a-z]* bash-3.1$ ls readme Page 66

67 Wildcards Some Practical Examples....bash_profile.cb.cshrc README dirlist stderr stdout wclist bash-3.1$ ls * README dirlist stderr stdout wclist bash-3.1$ ls -a * bash-3.1$ ls -a *.* bash-3.1$ ls -l.[a-z] bash-3.1$ ls.[a-z]* bash-3.1$ ls readme Page 67

68 Wildcards Some Practical Examples....bash_profile.cb.cshrc README dirlist stderr stdout wclist bash-3.1$ ls * README dirlist stderr stdout wclist bash-3.1$ ls -a * README dirlist stderr stdout wclist bash-3.1$ ls -a *.* bash-3.1$ ls -l.[a-z] bash-3.1$ ls.[a-z]* bash-3.1$ ls readme Page 68

69 Wildcards Some Practical Examples....bash_profile.cb.cshrc README dirlist stderr stdout wclist bash-3.1$ ls * README dirlist stderr stdout wclist bash-3.1$ ls -a * README dirlist stderr stdout wclist bash-3.1$ ls -a *.* ls: *.*: No such file or directory bash-3.1$ ls -l.[a-z] bash-3.1$ ls.[a-z]* bash-3.1$ ls readme Page 69

70 Wildcards Some Practical Examples....bash_profile.cb.cshrc README dirlist stderr stdout wclist bash-3.1$ ls * README dirlist stderr stdout wclist bash-3.1$ ls -a * README dirlist stderr stdout wclist bash-3.1$ ls -a *.* ls: *.*: No such file or directory bash-3.1$ ls -l.[a-z] ls:.[a-z]: No such file or directory bash-3.1$ ls.[a-z]* bash-3.1$ ls readme Page 70

71 Wildcards Some Practical Examples....bash_profile.cb.cshrc README dirlist stderr stdout wclist bash-3.1$ ls * README dirlist stderr stdout wclist bash-3.1$ ls -a * README dirlist stderr stdout wclist bash-3.1$ ls -a *.* ls: *.*: No such file or directory bash-3.1$ ls -l.[a-z] ls:.[a-z]: No such file or directory bash-3.1$ ls.[a-z]*.bash_profile.cb.cshrc bash-3.1$ ls readme Page 71

72 Wildcards Some Practical Examples....bash_profile.cb.cshrc README dirlist stderr stdout wclist bash-3.1$ ls * README dirlist stderr stdout wclist bash-3.1$ ls -a * README dirlist stderr stdout wclist bash-3.1$ ls -a *.* ls: *.*: No such file or directory bash-3.1$ ls -l.[a-z] ls:.[a-z]: No such file or directory bash-3.1$ ls.[a-z]*.bash_profile.cb.cshrc bash-3.1$ ls readme ls: readme: No such file or directory Page 72

73 Wildcards Some Practical Examples....bash_profile.cb.cshrc README dirlist stderr stdout wclist bash-3.1$ ls -a * README dirlist stderr stdout wclist Page 73

74 Wildcards Some Practical Examples....bash_profile.cb.cshrc README dirlist stderr stdout wclist bash-3.1$ ls -a * ; ls -a README dirlist stderr stdout wclist....bash_profile.cb.cshrc README dirlist stderr stdout wclist Page 74

75 Wildcards Some Practical Examples....bash_profile.cb.cshrc README dirlist stderr stdout wclist bash-3.1$ ls.*.bash_profile.cb.cshrc --> as you might expect. Page 75

76 Wildcards Some Practical Examples....bash_profile.cb.cshrc README dirlist stderr stdout wclist bash-3.1$ ls.*.bash_profile.cb.cshrc But you also get these!.: README dirlist stderr stdout wclist..: Basic-Gamma-Spectroscopy.pdf plugtmp CIN pdf pmwiki.php CRP pdf recipe py CRP pdf references_tables_online.pdf Configuration-Management-Nov2008.pdf saint_installation_test_case.pdf IDC LATEST.pdf WC Page 76

77 Deliberately blank... Page 77