Počeštění fontu
- dodání českých znaků [CZ]no guarantee
Last change: Aux 17, 2005
Počeštění fontu
- dodání českých znaků [CZ]Sections: help | Directories+files | Processes | Text utils | Network | Permissions/Access rights | X server | Other
Getting help -----------------------------------
apropos keyword - returns all the first lines of man entries
that include the keyword. The first line is st. like:"xedit - simple X text
editor". (But a special database must be set up.) It search a database that
must be initialized (e.g. run 'root# mandb -c') and should be kept
up-to-date.
man - shows a manual page for a command / utility (e.g. man
ls, man gcc). See below.
Directories and files --------------------------
cd directory - change dir., as in DOS (cd
subdirectory | cd .. | cd absolut_path). cd without an
argument enters your home directory ("cd" equals to "cd $HOME"). cd -P
../ goes to the real parent directory ignoring the symlink you used to
come there.
cp source target - copy 'source' and name it as 'target'. For copying
directories add '-r' flag (it ensures copying of all subdirectories etc., r
means recursive):
$> cp -r ../source.directory
target-directory.
ln - creates hard or soft link (i.e. a 'file' that points to another
file). Use flag -s for a symbolic (soft) link.
ls - lists a content of a directory (as 'dir' in DOS). If you type
ls -la more detailed information will be shown ('l' as long format
and 'a' as all files).
mkdir directoryname - make directory
mv source target - moves a file from source to target
$> mv $HOME/java/file.class
$HOME/cool_java // moves file.class from /java to /cool_java
pwd - prints current work directory
rm [options] name - remove file or directory named name.
If removing non empty directory, then use the following:
$> rm -r directoryname . Some flags:
-i asks for confirmation, -f forces the removal without asking.
shred - delete a file securely, first overwriting it to hide
its contents
Processes ------------------------------------
bg/fg - brings a process to background/foreground
kill a process: 1)find it (ps -alef | grep
probable_name) 2) kill it (kill -9 process_id)
(note: sometimes better to use only "ps -al"; Also ps has a flag -format that
let you choose what you want to see [e.g. pid&name...])
top display CPU, memory (...) and disk usage of processes (press 'q'
to quit it)
fuser prints what processes are using a file/filesystem -
indispensable if you can't umount/remove floppy because something i s using
it and you don't know what
Text utils -----------------------------------
bhl (GNU made) converts plain TXT files into HTML, LaTeX, and
SGML
cat file1 [file2 ...] concatenates the files and
prints them to the screen (->split)
conv (also dos2unix and
unix2dos) convert a text file from DOS to UNIX and vice versa
(EOFs). Try also iconv ($ conv -f ISO8859-2 -t
WINDOWS-1250 in.txt > out.txt).
cut cuts a file into columns (->paste). Ex (print to the screen
2nd word (separator=space)):$> cut -d" " -f2
myfile
grep (see also agrep - a better grep)- searches specified
files (if none, searches all files in the current directory) for a pattern,
prints out all lines containing the pattern (+filename +line number). It's
case sensitive until the flag '-i' is used. Flag -l: print only a list of
files containing >=1 matched string. Flag -n causes it to print line
numbers (starting with 1). Flag -v inverts result (prints lines not
containing the pattern). $> grep -i
'mystring' * finds & prints all lines of all files in the
current pwd, containing pattern 'mystring' or 'Mystring' etc. (case
insensitive). Note: with flag '-w' it doesn't match substrings (-w 'les' do
not match 'lesnice'). See xargs below to see how to
search recursively. $> grep -E '^a?b|c'
inputfile finds all lines starting with a, ab, or c.
head displays the beginning of a file (->tail)
less - better version of 'more'. See also lesskey (lets you
customize key bindings ['f' for 'forward' ...]). See the "more" command. See
also
lesspipe.sh:
an input filter forless that allows to view files with binary
content,compressed files, archives and files contained in archives
more prints a file to the screen (less is similar and
better but not that common)
paste joins files created by cut (or actually any files as long as
they have the same number of lines) (->cut)
recode changes file coding (e.g. iso-8859-2 to windows-1250).
Similar but simpler is iconv, which is a part of glibc and thus
shall be installed on every system.
sed - stream editor ex.: substitute (s) every line (matched by
'.*' and referenced by '&') by st. else (sed s/RegExp/ByWHAT/):
$> sed 's/.*/<option value="&">&<\/option>/'
in.file.txt // '/' must be escaped. Ex - extract file extensions from
a file list and print them, ignore all non-matching lines ( -n don't print
lines by default; /p print the line): $> sed -n
's/.*\.\(.*\)/\1/p'
sort [-u] file1 [file2 ...] concatenates the files and sorts
them. Any duplicates are removed if -u is given.
split splits files into blocks of the same length
tail displays the and of a file (->head)
tee is used in a pipe to print to the standard output (the screen)
what's passing through it: ... | tee | ...
tr "translates" a character (also [:space:] etc.) into another,
i.e. replaces all occurrences of a character in a file by another one. Ex
(dos files to unix format = delete LF?):$> tr -d
'\r' < dos_file > output_unix_file. Ex2 - Change to
lowercase: $> cat file | tr '[A-Z]'
'[a-z]'
unique
wc file counts words, lines etc. of a file
Network --------------------------------------
hostname [i] - print computer's hostname (or IP, if the i flag
is given)
scp "secure copy", similar to cp but copies between a local and a
remote machine. It uses SSH (thus the remote system must run ssh daemon, i.e.
sshd).
sftp secure ftp, quite the same as ftp but instead of ftp daemon
it uses ssh daemon (= ssh server)
stat [-f] print status of a file - size, last acces time etc.
wget non-interactive tor for web downloading (you can start it and
log off, it goes on working). wget --spider --force-html -i
file.html checks links.
route - print routing tables.
netstat -pl - show what program (-pid) is listening (-l) on which
port, i.e. which program opened a port. Must be run by root to display the
program's name and PID.
Permissions/Access rights
-------------------
newgrp group_name changes user'a effective group to the
given one. If you want to gain permissions valid for one of groups you belong
to and it isn't your effective one (see id) you have to switch into it via
newgrp.
chmod [who] op-code permission file - [who] may be 'o' (others),
'g' (group), 'u' (login owner), 'a' (all above). Op-code may be '+' (add
permission), '-' (remove perm.), '=' (set permissions), permission may be
any sub-string of string 'rwx' (r as read, w s write, x as execute). File is
the name of the file, whose permission is being changed. Ex: $>chmod o=r
myfile sets permission for others only to read (others can only read file
myfile, not write or execute)
id prints effective user id and username as well as effective
group id (gid) and its name.
groups prints what groups the user belongs to, the effective one
(the one that is valid for him/her in the moment) goes first
chown, chgrp change owner/group of a file
addgroup,delgroup,adduser,deluser used by root to add/delete
X server ------------------------------------
xev - print contents of X events - use this e.g. to learn what
key code is assigned to a key.
setxkbmap - changes the keyboard (what character is typed
when you press a certain key). Ex - set Czech: $> setxkbmap cz_qwerty
-model pc105 -option // See /etc/lib/X11/xkb/; there is a file "symbol"
that contains all known layouts (cz_qwerty, us ...). See also: xmodmap (or
its graphical front-end xkeycaps). Or: $> setxkbmap cz_qwerty
back: $> setxkbmap us
xmodmap, xkeycaps - set a keyboard mapping. xkeycaps is a
graphical front-end to it, you can see what key corresponds to what
character/symbol. "$> xmodmap -pk" lists the current keymap table.
xdpyinfo - display info about the X server (current resolution,
etc.)
Other ---------------------------------------
clear - clears the shell window. CTRL-l has the same effect. (CTRL
stays for the Control key)
du -k directory prints the space occupied by the directory (and
the same for its subdirs & files); -k = the values are in KB. (df
prints file system usage info) Ex.: $> du
-m --max-depth=5 | sort -nrk 1 (sort according to the first
field which is a number, largest first).
echo - to print something. E.g. $> echo
$MODULEPATH to see the content of varible MODULEPATH (don't
forget '$' sign) To print environmental variables, you can use printenv
instead (e.g. $>printenv
MODULEPATH)
env - prints all variables and their values (SHELL ...).
eject eject CD-ROM
find pathname_list condition - finding a file. Pathname-list -
where should it search (e.g. ~mnt/floppy, ../mydir, ./, .) Conditions - see
man for complete list (e.g. -name filename, Search for more
files: find . -name filen1 -o -name filen2). See the command slocate
below. Flag -xdev causes not to search other filesystems (e.g. mounted in
/mnt/*). Ignore dir. "dir": find -path '*/dir'
-prune -o -print .
getopts is used in scripts to parse arguments from the commend
line (prefixed by - or +). See a description.
less - better version of 'more'. See also lesskey (lets you customize
key bindings ['f' for 'forward' ...]). See the "more" command. See also lesspipe.sh:
an input filter forless that allows to view files with binary content,
compressed files, archives and files contained in archives
lp - printing (use "psnup -n 2" to fit to pages on one; takes a
.ps file as input, output can be sent to printer via pipe: ... | ls)
module - module add
name and module initadd
name (where name referes to the module to be added, w.r.t.
path specified in MODULEPATH)
more - displays its input (a file, stdin) on the screen only it is
full and then waits. Press "h" in it for help. Similar but better is
less.
passwd - change your password
quota -v prints the current total usage and the quota (for
disc space)
rpm -iv file.rpm install a rpm package (not tested)
set, unset - change value of a variable in bash (e.g.
$>setenv PATH $PATH":/student/bin").
Sometimes called setenv, unsetenv.
locate <string> or slocate - finds <string> in
the database of files. Quite faster than find. The database must be
initialized before.
/sbin/shutdown (-h | -r) 0 shut down / restart computer in 0
ms. See also: /sbin/halt, poweroff, reboot.
su [-] [<user>] run a new shell as the user
<user>. If '-' is omitted his/her login scripts are not executed. No
user = root.
sudo [ <user>] <command> -
execute a command as another user (no user = root). What can be done in this
way is written in the file sudoers.
test - check file types and compare values (existence, size
...) - very useful, many possibilities. Short version of this is '[
'...' ]'.
which command_name - prints PATH for the command
command_name (or "command not found"). Ex: $> which java.
xargs utility [arguments] - basically
takes standard input and construct a command line of the form "utility
[arguments] read_from_input". Ex: $> find net/
-name "*.java" | xargs grep -n 'Network' finds all .java files in
the current dir and its subdirs and then let grep search through them for the
string 'Network'.
You can see a long list of programs available on my system (in Swedish).
Notes:
It can be also useful to find information on man itself ($> man man).
See the command apropos (above).
There exists a set of utilities for accessing DOS disks (including floppies) under UNIX. See $> man mtools for details. Notice that you can use these tools as well to access MS Windows files.
For more info, search "$man bash" for "REDIRECTION".
| - connects two programs via a pipe (runs the first and then the 2nd, output of the first one becomes input of the second one): $> program1 | program2To set redirection for a group of commands you can enclose the commands by
'{ ' and ' }':
$> { echo "cmd1"; echo "cmd2"; } > /dev/null
.
GNOME windows manager was Sawfish, nowadays it's Metacity (better integration). GNOME uses GTK library for GUI. GLib - objects for C; lib Pango - visualization of text; lib ATK - accessibility support for handicaped.
KDE uses Qt (C++ library). DCOP - system for communication among applications + user scripting. See kdcop. Ex:
dcop |
kdesktop |
KBackgroundIface |
changeWallpaper |
... |
| ^ client | ^ object | ^ command | ^ parameters |
Let's call the first computer "server" and the other one "client". IPs 192.168.1.x are allocated to private networks, they can never appear on the internet; 192.168.1.0 is address of the network, you can use e.g. addresses 192.168.1.1 - 192.168.1.254. (Class C is 192.168.0.0 - 192.168.255.255)
I shall present here some basic terms related to video. My explanation is quite naive as I don't know much about it myself so sorry for inaccuracies.Read more e.g. in the documentation of MPlayer.
You can grab video from a stream e.g. with the VLC media player. The resulting file is likely to be quite huge. You can compress it by encoding it - use e.g. avidemux. It's quite easy to encode with Avidemux (v. 2.0.38):
ernest -
Documentation, tutoriaux Unix/Linux en francais