All Stuff and More: Usefull linux commands

find folderABC -mtime -9 -- show files in and below folder ABC modified less than 9 days ago
find ~ -name font* -print -- show files and folders in my home folder and below starting with the work 'font'
find . -type f $ -iname *.jpg -o -iname *.jpeg $ -- find only files with extension jpg or jpeg
find . -type f -path ./.config -prune -false -o -iname.jpeg -- skip files with and 'Android' in path
ps

ps aux | grep myprocesspartialname - not no '-' before the options
/bin/ps -context -www -p processID -- shows wide command line for the process

svn diff -r HEAD fileABC -- compares the file ABC to its most recent version in the repo
zip+unzip:

tar -czf file.tar.gz file1 file2 file3 -- create a gzipped archive file.tar.gz with three files in it
tar -xzf tar-file-name.tar.gz

search - just like in vi, by hitting / you can search by specifying a regex pattern
to search for a whole word: \<...\>
to escape a special char, for example to search for a path, do: \/opt\/jboss
to cut lines into a vim internal clipboard, use dd command.
option :set-nowrap turns of the default, and sometimes annoying, line wrapping
to toggle word wrapping, use command: :set wrap!
to do case-ignore search do /\cAlicja, and to do case sensitive search use \C
to mark a location type m L, where L is any letter, e.g. m a, and to move back to this location type: ' L (single apostrophe)
to place the current line at the top, center or bottom, hit zt, z., or zb.

symbolic link: ln -s target link-name
To me, it seems backward, but I guess you can say it like this: take target and call it link-name

remove: rm -r folder-name
(note: rmdir will delete only an empty folder)
copy: cp -r folder-name dest-folder-name
with -f option, you can avoid any questions
by convention: folder/* means contents of the folder, while folder/ means all of the folder

-wBb file1 file2 -- diff two files with all whitespaces ignored (new lines are not ignored-this is a much more complex problen, even just conceptually)
-r dir1 ird2 -- recursively, shows files found only in one of the trees, for binaries shows message "files different"

du which tells "how much of the precious space does a this folder or files use":

du -sh my-folder/* -- shows size of all files and folders in my-folder folder, one number per file/folder

df -h which shows you the list of the files systems and which of them full if any.

ignoring the useless Permission denied entries. Can be done using a redirection: grep my-cat-Lois my-folder/Lois-files 2> /dev/null
with a regex. The simplest regex to find one or more tabs in the file was:
grep '^This[[:space:]]\+5' parms*.txt
to show only the file names, use option -l
to search through compressed .bz2 files, use bzgrep instead of grep
to search for words, use option -w

su and sudo -- both can take a user as a parm (superuser by default). The su switches to that user until you do exit, while sudo is followed by a command, that only this one command is executed in the assumed user context.
chown -R jboss:jboss_grp * -- change ownership of all files in this folder and below to user jboss, group jboss_grp.
adduser username -- add a new user and add user to the group. Once the user is created, to add user to the sudo group, repeat the same command with one more argument at the end: sudo
usermod -a -G sudo jdoe -- add user to group sudo
passwd user1 -- change password for user1. Use option -e to have force user to change it at the first login.
awk -F '\t' ' /^Product\t/ {print $7} ' file.txt

-F - Tab as a separator (deault: spc)
'...' - program, inline
default program structure: condition action
Together: above command prints 7th (tab-separated) element of all lines of file file.txt that start with 'Product\TAB'
a bit more complex script: { if( $0 ~ /^Fund\t/ && $10 == "False") {print $13} } -- It prints 13th element of the record, but only for lines starting with 'Fund', where the element 10th is 'False'.
and, if you need to process mutliple files, one option is a shell script:
#!/bin/bash
for var in $(ls /var/GOLL/import/exportPP_*.txt); do
ls -l $var
awk -F '\t' ' { if( $0 ~ /^Fund\t/ && $10 == "True") {print $3, $6, "ClosedDate:", $8, $10, $11, $12, $13} }' $var
done

dmsg show system messages, e.g. out-of-memory errors and processes killed as a result
working in command line:

less, tail and vim - you can open a file to view anypart of it using vim-like commands and switch to the 'tail -f' mode with Ctrl-F. Then, Ctrl-C will take you back to viewing the whole file.

mkdir -p /var/dir1/dir2 -- create directory with all its missing parents
getfacl folder -- show details of custome access specs for a folder (it shows as + on the long directory/file listing)
cat /etc/*release -- show the name and version of the OS

groups [user] -- show groups that user belongs to (by default - this user)
groupadd grouptoadd -- creates a new group
cat /etc/group -- shows one line per group with all its members; grep the list as needed
gpasswd -a user group -- adds user to the group (-d for delete from the group)

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