Some Unix Commands

Accessing Rucs

• Use a putty (or ssh) session from a windows machine


• Directory /home/userid is your H: drive


• Remember: Unix/Linux is Case Sensitive!


• Using submit: submit command must be executed on rucs and the file must be on H: drive

Some Example Unix Commands

• Query file information:
• ls - list files


• Relative and Absolute Paths
• Absolute Paths: Begin with / or ~
• Relative Paths: Begin with directory or file name or . or ..


• ~ - your home (ie H:) directory
• . - the current directory
• .. - the parent of the current directory


• Navigate among directories (ie among folders)
• cd - change directory


• View file contents:
• cat f1 - view contents of file f1 (concatenate)
• less f1 - view contents of f1 a screen at a time
• more f1 - less powerful version of less
• head f1 - see beginning of f1
• tail f1 - see end of f1
• diff f1 f2 - difference between files or directories f1 and f2


• Manipulate files:
• cp f1 f2 - create copy of f1 either named f2 (if no directory f2 exists) or in directory f2 (if directory f2 exists)
• mv f1 f2 - rename (move) file f1 to f2
• rm f1 - delete (remove) file f1
• touch f1 - create f1 as an empty file


• Manipulate folders:
• mkdir - make a directory
• rmdir - remove a directory (must be empty)


• Help:
• man com - help on command com


• Words in files:
• wc f1 - word count of file f1
• grep s f1 - search for string s in file f1


• Path and Environment:
• which/whereis - What is executed
• echo $path -
• printenv - Environment variables


• Other:
• cls - clear screen


• Redirection and pipe:
• | - pipe
• < - redirect in
• > - redirect out
• >> - redirect out and concatenate

Command: ls

• List files


• Examples:
• ls - list names of files in current directory
• ls -l - list long format (ie name, size, date, protection) of files in current directory
• ls *.adb - list any file that has ".adb" as an extension
• ls -l *.adb - list in long format any file that has ".adb" as an extension
• ls -l ../*.adb - do the same in the parent directory
• ls -l ~/*.adb - do the same in the home directory (ie h: drive)


• Options:
• ls -l - long format
• ls -a - all files
• ls -f - all files
• ls -F - mark directories and executables
• Similar windows command: dir

Absolute and Relative Path Names

• Absolute Paths: Begin with / or ~
• Relative Paths: Begin with directory or file name or . or ..


• ~ - your home (ie H:) directory
• . - the current directory
• .. - the parent of the current directory


• Example: ls -l proj1/g1.adb

Command: cd

• cd dir - Change to directory dir


• Example:

    cd proj1
    cd ..
    cd proj2
    cd ../proj3
    

• Similar windows command: cd

Command: cat

• Concatenate files
• cat foo.adb - displays contents of foo.adb
• Similar windows command: type

Commands: less, more

• display a file, one screen at a time
• less foo.adb - displays contents of foo.adb
• Use spacebar to progress, ^-b to go backwards, q to quit
• more - Similar to less, but more restricted (original version called more, newer cleverly called less)

Commands: head, tail

• head f1: display the first few lines of file f1
• tail f1: display the last few lines of file f1

Commands: diff

• diff f1 f2: display the difference between files f1 and f2
• diff f1 f2: display the difference between directories f1 and f2

Command: cp

• copy one file to another or to a directory


• cp foo.adb foo2.adb - creates foo2.adb as a copy of foo.adb


• cp proj1/foo.adb submitted - creates foo.adb as a copy of foo.adb in directory submitted


• cp ~/foo.adb . - copies foo.adb from the home directory to the current directory


• cp ~/foo.adb ./foo2.adb - copies foo.adb from the home directory to the current directory and gives it a new name (in the current directory)


• cp ~/320/proj1/* dummy - copies all regular files (not directories) from directory proj1 to existing directory dummy

Command: mv

• move a file (or rename it)


• mv foo.adb foo2.adb - changes name of file foo.adb to foo2.adb


• mv ~/foo.adb . - moves foo.adb from the home directory to the current directory


• cp ~/foo.adb ./foo2.adb - moves foo.adb from the home directory to the current directory and gives it a new name

Command: rm

• remove a file


• rm foo.adb - deletes file foo.adb


• Really removes the file - does not move it to a garbage can


• Does not work on directories (unless you use -r, but CAREFUL of this command)


• Similar Windows command: del