alias assigns an alias for commands, files or devices. Only available in the C shell.
cat concatenates (joins) files and lists the result. Often used to direct the contents of a single file to the standard output.
-n numbers the lines in the file(s)
-s eliminates consecutive blank lines
Example: % cat file1 file2 > file3
cd [directory] changes current working directory. (Default is home directory.)
Example: % cd /usr/etc
chmod mode file changes permissions of files and directories. Mode consists of three elements: [ugoa] [+-=] [rwxs]
Example: % chmod g+r project (adds read permission to group)
cmp compares two files and prints the line number and character where they differ.
Example: % cmp file1 file2
comm compares two files for common lines.
-1 suppresses lines that only occur in file1
-2 suppresses lines that only occur in file2
-3 suppresses lines that only occur in one file
cp makes a copy of a file.
-i interactive mode (to protect destination file if it already exists)
Example: % cp -i file1 file2
date gives time and date
diff lists differences in two files or directories.
-b ignores trailing blanks
-e prints ed changes needed to make files identical
ed accesses the ed line editor
grep searches a file for a pattern (see chapter 15)
head -n Prints first n lines
jobs lists the background jobs.
-1 displays process id
kill terminates background job
ln -s sets up a symbolic link to a file or directory.
Example: ln -s /usr/games fun
ls lists files in a directory (default current directory)
-a all files (including hidden files)
-c in order of creation time
-g give group identity
-l in long format
-s sorted by block size
-t sorted by modification time
-u sorted by last access time
mail receives and sends mail
mkdir creates a directory
more lists the contents of a file a page at a time.
mv moves a file. Often used to simply rename a file.
-i interactive mode to protect destination file if it already exists
passwd change passwd
pg pager available on some systems
pr formats and outputs a file.
-ln where n is the page length (default 66)
-wn where n is the page width (default 72)
-n no. of columns
-hstring defines the header name as string
pwd displays name of current directory
rm deletes files
-i interactive prompt to protect files
rmdir delete directory (only works on empty directories).
sort sorts and merges files.
-b ignores blanks
-d dictionary order
-f fold upper to lower case
-i ignores characters outside the printable ASCII set
-n sorts numbers by value
-o directs output to a file
-r sorts in reverse order
spell checks spelling in a file
tail n lists the last n lines of a file if n is negative, or starts listing on the nth line, if n is positive
time displays the execution time of a command
unalias removes a previously defined alias
vi accesses the vi screen editor
wc counts the number of lines, words and characters in a file
-c counts only characters
-w counts only words
-l counts only lines
who who is logged on
write direct communications to users on the same machine