(c) faisal akkawi & munki lee 2001basic unix commands1 faisal akkawi [email protected]...
TRANSCRIPT
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 1
Basic UNIX Commands
Faisal Akkawi
Department of Computer Science
Illinois Institute of Technology
Chicago, IL 60616
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 2
Topics Handling Files and Directories Text Editors Compiling and Linking Handling Processes Archiving and Compressing Files Other Useful Commands
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 3
Handling Files and Directories ls : list files cp : copy files mv : move files rm : remove files mkdir : make directories cd : change directories rmdir : remove directories pwd : print working directory chmod : change permission mode umask : set file-creation mode mask
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 4
ls command Syntax
ls [-Options] [name ...] Description
Lists contents of directory. Frequently Used Options
-a List all entries, including . and .. -d Do not list contents of directories -l Long listing -F Mark directories with a '/', etc.
Examples ls -alF
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 5
cp command Syntax
cp [-Options] file1 [file2 ...] target Description
File1 is copied to target. Frequently Used Options
-f Force remove existing file -i Ask before removing existing file -r Copy directory trees
Examples cp p1.c p2.c cp p1.c p2.c mydir
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 6
mv command Syntax
mv [-Options] file1 [file2 ...] target Description
File1 is moved to target. Frequently Used Options
-f Removes existing files without prompting the user -i Asks before removing existing file
Examples mv p*.c mydir
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 7
rm command Syntax
rm [-f] [-i] file . . . rm -r [-f] [-i] dirname . . . [file . . .]
Description Removes files or directories.
Frequently Used Options -f Removal of files without prompting the user -i Interactive removal -r Recursive removal
Examples rm -f p*.o rm -r mydir
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 8
mkdir command Syntax
mkdir [-m mode] [-p] dirname . . . Description
Creates the specified directories. Options
-m Specifies the mode to be used -p Create missing intermediate directories
Examples mkdir -m 700 letter mkdir abc mkdir -p ./abc/def/ghi
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 9
cd command Syntax
cd [directory] Description
Change working directory. If directory is not specified, the value of shell
parameter $HOME is used as the new working directory.
Examples cd cd ./abc/def/ghi cd ..
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 10
rmdir command Syntax
rmdir [-p] [-s] dirname . . . Description
Removes directories. Options
-p Remove the directory dirname and its parent directories which become empty.
-s Suppress the message when –p is in effect Examples
rmdir letter
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 11
pwd command Syntax
pwd Description
Prints the path name of the working (current) directory.
Examples pwd
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 12
chmod command Syntax
chmod [-R] mode file ... chmod [-R] [ugoa]{+|-|=}[rwxXstl] file ...
Description Changes the permissions mode of a file or directory.
Examples chmod 444 file1 chmod ugo+rw p*.c chmod 700 mydir
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 13
umask command – I Syntax
umask [ooo] Description
Sets file-creation mode mask to ooo. The three octal digits refer to read/write/execute permissions for owner, group, and others, respectively.
The value of each specified digit is subtracted from the corresponding ‘digit’ specified by the system for the creation of a file.
If ooo is omitted, the current value of the mask is printed.
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 14
umask command – II Examples
umask 022 removes group and others write permission (files normally created with mode 777 become mode 755; files created with mode 666 become mode 644).
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 15
Text Editors pico
- Simple, easy-to-use text editor vi
- Text editor based on an underlying line editor ex emacs
- Powerful and extensible
- Hard to learn
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 16
pico Layout is very similar to the pine mailer
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 17
vi vi Modes:
Command mode : Normal and initial mode. Other modes return to command mode upon completion. ESC (escape) is used to cancel a partial command.
Input mode : Entered by setting any of the following options: a A i I o O c C s S R . Arbitrary text may then be entered. Input mode is normally terminated with ESC character.
Last line mode : Reading input for : / ? or !.Terminates by typing a carriage return
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 18
Compiling and Linking cc
- C compiler
- Default behavior is ANSI/ISO C make
- Allows programmer to maintain, update, and
regenerate groups of computer programs.
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 19
cc command – I Syntax
cc [-Options] ... file ... Description
*.c are assumed to be C source programs. *.o are compiled object files. a.out is the default output program name.
Frequently Used Options -c Produce an object file -O Invoke optimizer
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 20
cc command – II -o out Name the final output file out. -Dname Define the name to the C macro processor -Idir Seek dir for include files
Examples cc p1.c
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 21
make command Syntax
make [-f makefile] [-eiknpqrsStuwdDPBNMOg] [names]
Frequently Used Options -f makefile Description file is makefile -n Print commands, but do not execute them. -u Build all targets regardless of whether they are
up-to-date or not. Examples
make make –f Project1.mak
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 22
Handling Processes ps : Prints information about active processes kill : Sends a signal to a process ipcs : Reports IPC facilities status ipcrm : Removes IPC resource id
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 23
ps command Syntax
ps [-Options] Description
Prints information about active processes. Frequently Used Options
-A Every process now running -e Same as -A -f Full listing -l Long listing
Examples ps -ef
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 24
kill command Syntax
kill [-signal] pid . . . kill –l (the letter ‘L’ in lowercase)
Description Sends a signal to the specified processes. The value of signal may be numeric or symbolic. Signal 15 is the default signal. kill –l lists the defined signals.
Examples kill 389 kill –3 401 402 kill -HUP 99999
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 25
ipcs command Syntax
ipcs [-Options] Description
Prints information about active IPC facilities. Without options, information is printed for message
queues, shared memory, and semaphores that are currently active in the system.
Frequently Used Options -q Message queues -m Shared memory segments -s Semaphores
Examples ipcs -q
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 26
ipcrm command Syntax
ipcrm [-Options] Description
Removes messages, semaphore or shared memory identifiers.
Frequently Used Options -q msqid Removes the message queue id -m shmid Removes the shared memory segment id -s semid Removes the semaphore id
Examples ipcrm -q 231
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 27
Archiving and Compressing tar : Tape archiver compress, uncompress, zcat : Compresses and
expands data using adaptive Lempel-Ziv coding gzip : Compresses data using Lempel-Ziv coding gunzip, gzcat : Decompresses files created by gzip,
zip, compress, or pack pack, unpack, pcat : Compresses and expands files
using Huffman codes
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 28
tar command - I Syntax
tar key [arguments] [name...] Description
Saves and restores multiple files on a single file. The key argument controls tar's actions.
Frequently Used Functions c Create x Extract from the tape t List files on the tape
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 29
tar command - II Frequently Used Modifiers
v Verbose f Next argument is the name of the
archive
Examples tar cvf my.tar ./mydir1 ./mydir2 tar tvf my.tar tar xvf my.tar
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 30
compress command Syntax
compress [ -f ] [ -v ] [ -c ] [ -V ] [ -d ] [ -b bits ] [ name ... ] Description
Compresses and expands data Compressed file name is *.Z
Frequently Used Options -c Write output on standard output -d Uncompress -v Verbose
Examples compress my.tar compress -d my.tar.Z
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 31
uncompress command Syntax
uncompress [ -f ] [ -v ] [ -c ] [ -V ] [ name ... ] Description
Uncompresses files Same as compress –d
Frequently Used Options -c Write output on standard output -v Verbose
Examples uncompress my.tar.Z
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 32
zcat command Syntax
zcat [ name . . . ] Description
Uncompresses files Same as uncompress –c Writes the uncompressed data on standard output
Examples zcat my.tar.Z > my.tar
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 33
gzip command Syntax
gzip [ -acdfhlLnNrtvV19 ] [-S suffix] [ name . . . ] Description
Compresses and expands data Suffix .gz
Frequently Used Options -c Write output on standard output -d Uncompress -h Help -r Recursive -v Verbose
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 34
gunzip command Syntax
gunzip [ -acfhlLnNrtvV ] [-S suffix] [ name ... ] Description
Uncompresses files (Same as gzip –d ) Automatically detects input format
Frequently Used Options -c Write output on standard output -h Help -r Recursive -v Verbose
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 35
gzcat command Syntax
gzcat [ -fhLV ] [ name . . . ] Description
Uncompresses files (Same as gunzip –c) Writes the uncompressed data on standard output
Examples gzcat myfile.gz > myfile
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 36
pack command Syntax
pack [ - ] [ -f ] name . . . Description
Compresses files Suffix .z Directories cannot be compressed
Options -f Force packing
Examples pack myfile
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 37
unpack command Syntax
unpack name . . . Description
Expands files created by pack Each .z files is replaced by its expanded version The new file has the .z suffix stripped from its name
Examples unpack myfile.z
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 38
pcat command Syntax
pcat name . . . Description
Uncompresses files created by pack Files are unpacked and written to the standard output
Examples pcat myfile.z pcat myfile pcat myfile.z > myfile
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 39
Other Useful Commands grep : search files for a pattern man : on-line reference manuals wc : word, line and byte or character count
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 40
grep command - I Syntax
grep [-E| -F] [-c| -l| -q] [-insvx] pattern_list [file . . .]
Description Searches the input files, selecting lines matching one
or more patterns Frequently Used Options
-i Case-insensitive search -l Write file names only -n Display line number
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 41
grep command - II Examples
grep -i unix p1.c grep -n UNIX *.c *.h ps –ef | grep mary
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 42
man command Syntax
man [-Options] [-M path] [-T macropackage] [ -s section] name ... man [-M path] -k keyword ...
Description On-line reference manuals
Frequently Used Sections 1 User commands and application programs 2 System calls 3 Library functions
Examples man -s 1 mkdir man mkdir man -k pipe
(c) Faisal Akkawi & Munki Lee 2001 Basic UNIX Commands 43
wc command Syntax
wc [ -c|-m ] [ -lw ] [ file . . . ] Description
Counts lines, words, and characters Options
-c Count the number of bytes -m Count the number of characters -l Count the number of newline characters -w Count the number of words
Examples wc -l *.h *.c