# file:linux-cheat-sheet.sh v.1.9.5 docs at the end
# get a nice prompt
export PS1=" \u@\h [\d \t] [\w] $ \n\n "
export PS1="\h [\d \t] [\w] $ \n\n "
# aliases
# show dirs with nice time newest modified on top
alias ll='ls -alrt --time-style=long-iso'
to_srch='what_to_srch'
to_repl='what_to_replace'
#-- srch and repl %var_id% with var_id_val in dirs in $component_name_dir_tmp
find "$dir" -type d |\
perl -nle '$o=$_;s#'"$to_srch"'#'"$to_repl"'#g;$n=$_;`mkdir -p $n` ;'
find "$dir" -type f |\
perl -nle '$o=$_;s#'"$to_srch"'#'"$to_repl"'#g;$n=$_;rename($o,$n) unless -e $n ;'
#-- srch and repl %var_id% with var_id_val in files in $component_name_dir_tmp
find "$dir" -type f -exec perl -pi -e "s#$to_srch#$to_repl#g" {} \;
find "$dir/" -type f -name '*.bak' | xargs rm -f
# find the only the uniq file names of specific file type
find `pwd` -name '*.xml' | perl -pe 's/(.*)(\\|\/)(.*)/$3/;' | sort | uniq -u
# how-to find in files - e.g. search by a perl regex in files and redirect the output to vim
find `pwd` -name '*.pm' -exec grep -inHP -A 1 'sub [a-zA-Z0-9]*\s+\{' {} \; | vim -
# how-to search for a regex and build the ready open vim to found line cmds
find $dir -name '*.ext' -exec grep -nHP 'regex' {} \; | perl -ne 'm/^(.*):(\d{1,10})(.*)/g;print "vim ". "+$2 " . "$1 \n"'
# get system info
cat /proc/cpuinfo | less
cat /proc/meminfo | sort -nr -k 2 | perl -ne 'split /\s+/;printf ("%-15s %20d MB \n" , "$_[0]" , ($_[1]/1024))'
fdisk -l
# go the previous dir you where
cd -
pushd .; popd
#how-to check opened ports with nmap
nmap -sT -O localhost
# get selinux security context
ls -al --lcontext $dir
# change the selinux security context
chcon -vR -u system_u -r object_r -t httpd_sys_content_t $dir
# use rsync to preserve permissions
rsync -v -X -r -E -o -g --perms --acls $src_dir $tgt_dir
rsync -v -r --partial --progress --human-readable --stats $src_dir $tgt_dir
rsync -v -r --partial --progress --human-readable --stats $src_dir/$f $tgt_dir/$f
while read line_with_spaces ; do sh /path/to/script.sh "$line_with_spaces" ; done < $file_with_lines_with_spaces
# nice listing
find . -type f -exec stat -c '%n %y' {} \; | sort -n | less
# check permissions effectively
find . -type f -exec stat -c "%U:%G %a %n" {} \; | less
export file_name_to_filter=infa-reporter
stat -c "%n %y" *.zip | perl -ne 'm/^(.*?) (.*)/g; printf "%-70s %-50s \n" , "$1" , "$2"' | sort -r -k 2 | grep -i $file_name_to_filter
# The ultimate "find in files"
find /etc/httpd/ -type f -print0 | xargs --null grep -nHP 'StartServers\s+\d' | less
for file in `find / -type f \( -name "*.pl" -or -name "*.pm" \) -exec file {} \; | grep text | perl -nle 'split /:/;print $_[0]' `; do grep -i --color -nH 'string_to_search' $file ; done ;
# or even faster , be aware of funny file names xargs -0
find / -name '*bak' -print0 | xargs --null grep -nPH 'curl'
# find and replace recursively
find . -name '*.html' -print0 | xargs -0 perl -pi -e 's/foo/bar/g'
# how-to check disk space
find $dir -maxdepth 2 -type d -exec du -B M --max-depth=1 {} \; | sort -nr | less
# find all the files greather than 100 MB , sort them by the size and print their sizes
find $dir -type f -size +2M -exec du -B M {} \; | sort -nr | less
du -B M --max-depth 3 $dir | perl -nle 's#\s+# #g;print' | perl -ne 'm/^(.*?) (.*)/g; printf "%10s %-50s \n" , "$1" , "$2"' | sort -nr -k1 | less
# how-to search bunch of tar.gz files
cmd="zgrep $StringToFind '{}' >> $FileToOutput"
find ${DirFindRoot} -type f -name ${nameFilter} -print0 | xargs -0 -I '{}' sh -c "$cmd"
# disk usage of users under the /home directory in MB
export dir=/data/reseller/tmp/;
clear;du -all --block-size=1M $dir --max-depth=2 | sort -n | perl -ne '@a=split /\s+/g;$a[0]=~s/(?<=\d)(?=(?:\d\d\d)+\b)/ /g;printf "%15s %10s",$a[0],"$a[1] \n" '
# show in megs and sort each folder
find $dir -type d -exec du --summarize -B M {} \; | sort -nr | perl -ne '@a=split /\s+/g;$a[0]=~s/(?<=\d)(?=(?:\d\d\d)+\b)/ /g;printf "%15d %10s",$a[0],"$a[1] \n" '| less
tcpdump dst 10.168.28.22 and tcp port 22
tcpdump dst 1.2.81.2.8.212
# record the current session via script
mkdir ~/scriptlogs
script -a ~/data/log/script/`date +%Y%m%d%H%M%S`_script.log
#/usr/bin is for normal user executables, /usr/sbin is for superuser executables, /usr/sfw is for external software (like gnu one), but provided with bundle of OS, /usr/ccs is for development utilities, usually not need for daily tasks like make, lex, yacc, sccs
# take the last 5 commands for faster execution to the temp execution script
tail -n 5 /root/.bash_history >> /var/run.sh
# I saw the command cd /to/some/suching/dir/which/was/very/long/to/type
echo so I redid it and saved my fingers
!345
#how-to check my history without the line numbers
history | cut -c 8- | grep env
# how to deal with command outputs
command | filtercommand > command_output.txt 2>errors_from_command.txt
# find the files having os somewhere in their names and only those having linux
find . -name '*os*' | grep linux | less
# find all xml type of files and display only the rows having wordToFindInRow
find . -name '*.xml' -exec cat {} \;| grep wordToFindInRow | less
# START === bash shortcuts
# Go to the beginning of the line you are currently typing on
Ctrl + A
# Go to the end of the line you are currently typing on
Ctrl + E
# move a word forward
Alt + F
# move a word backwards
Alt + B
# STOP === bash shortcuts
# how-to mount an usb stick
# remember to change the path other wise you will get the device is busy errror
mkdir /mnt/usbflash
mount /dev/sdb1 -t vfat /mnt/usbflash
umount /mnt/usbflash
#display the first 20 lines of the file
head -n 20 too-long-file
# how to restart a service initiated at startup
/etc/rc.d/init.d/sendmail start | stop | status | restart
# see all the rules associated with the firewall
iptables -L -n -v --line-numbers
gunzip *file.zip
# To start remote session click on the putty screen , configure putty
# settings to pull full screen with alt + Enter
# right click on the title bar , settings , change the font , copy
# paste from and to the terminal window text
# how to ensure the sshd daemon is running
ps -ef | grep sshd
# how to kill process interactively
killall -v -i sshd
# the most efficent way to search your history is to hit Ctrl R and
#type the start of the command. It will autocomplete as soon as there’s
#a match to a history entry, then you just hit enter. If you want to
#complete the command (add to it ) use the right arrow to
#escape from the quick search box ...
#How to see better which file were opened , which directories were visited
#type always the fullpath after the vi - use the $PWD env variable to
#open files in the current directory , thus after opening the file
#after:
#vi /$PWD , press tab to complete the name of the current directory ,
#type the name of the file. THUS AFTER RUNNING
history | grep vim
#of course the same could be seen from the /home/username/.viinfo file /files
#where to set the colors for the terminal (if you are lucky to have one
# with colors ; )
/etc/DIR_COLORS
open a file containing "sh" in its name bellow the "/usr/lib" directory
:r !find /usr/lib -name *sh*
go over the file and gf
#which version of Linux I am using
uname -a
#How to copy paste text in the putty window from client to server -
#click the right button of your pointing device
#How to copy paste text from the putty window from server to client -
#right-click the window title and select copy all to Clipboard.
#To restart a service
service sshd restart
#
service --status-all --- show the status of all services
# change the owneership of the directory recursively
chown -vR user$group $dir
# perform action recursively on a set of files
find . -name '*.pl' -exec perl -wc {} \;
for file in `find . -type f`;do echo cp $file ./backups/; done;
for file in `ls *.docx -1`;do echo cp $file ./backups/$file.`date +%Y%m%d%H%M%S`.docx;done;
# make Bash append rather than overwrite the history on disk:
shopt -s histappend
# henever displaying the prompt, write the previous line to disk:
PROMPT_COMMAND='history -a'
# than run the script
#how-to replace single char in file
tr '\t' ',' < FileWithTabs > fileWithCommas
# Allow access to the box from only one ip address
# create a backup file based on the timestamp on bash
cp -v fileName.ext fileName.ext.`date +%Y%m%d_%H%M%S`.bak
#check disk space
df -a -h | tail -n +2 | perl -nle 'm/(.*)\s+(\d{1,2}%\s+(.*))/g;printf "%-20s %-30s %-90s \n","$2",$3,$1' | sort -nr | less
df -a -B M | column -t | sort -nr -k 5
df -h ***
# how-to get running processes
ps -ef --forest
# how-to kill misbehaving process ... you will need to adjust the -f 2 part
# depending on the output of the ps -ef command above
for pid in $(ps -ef | grep procToFind | perl -ne 's/\s+/ /g;print $_ . "\n";' | cut -d ' ' -f 2) ; do echo kill -9 $pid ; done ;
for pid in $(ps -ef | grep chrome | perl -ne 's/\s+/ /g;print $_ . "\n";' | cut -d ' ' -f 2) ; do echo kill -9 $pid ; done ;
#how-to create relative file paths tar package recursively fromm a dir
cd $RootDirToStartRelativePathsFrom
tar -cvzpf $pckg_to_create.tar .
# exctract tar file into cd
tar -xvf $pck_to_exctract_to_cwd.tar
#how-to create tar archieve
tar cvf $archive_name.tar $dir/
#how-to unpack tar file
tar xvf $file
#how-to unpack gz archive
gzip -cd $file | tar -xvf -
# print line number 52
sed -n '52p' # method 1
sed '52!d' # method 2
sed '52q;d' # method 3, efficient on large files
# START === create symlink
export target_path=/cygdrive/c/var/anc
export link_path=/nz/anc
mkdir -p `dirname $link_path`
unlink $link_path
ln -s "$target_path" "$link_path"
ls -la $link_path;
# STOP === create symlink
# START === user management
#how-to add a linux group
groupadd -g "$gid" "$group"
cat /etc/group | grep --color "$group"
#how-to add an user
useradd --uid "$uid" --home-dir "$home_dir" --gid "$group" \
--create-home --shell /bin/bash "$user" \
--comment "$desc"
cat /etc/passwd | grep --color "$user"
# modify a user
usermod -a -G $group $user
# change the password for the specified user (own password)
passwd $user
#how-to forces to change password when logging in for the first time
passwd -f login
#change user pass to expire never
chage -I -1 -m 0 -M 99999 -E -1 $user
# and check results
chage -l $user
#Ei should not return anything !!!
passwd -s -a | grep NP (=No Password)
#delete an user
userdel $user
#administer the /etc/group file
gpasswd:
# START === user management
#how-to extracts rpm packages contents
export ins=foo-bar.rpm
rpm2cpio $ins | cpio -id
#how-to extract *.tar.gz
gzip -dc *.tar.gz | tar xvf -
cd foo-bar-dir
#--- show all installed packages
rpm -dev
#how-to build binaries as a non-root
./configure --prefix=$HOME && make && make install
#exctract a single file:
gzip -dc fileName.tar.gz | tar -xvf - filename
find . -name '*.log' -print | zip cipdq`date +%Y%m%d%H%M%S` -@
# find several types of files
find . -type f \( -name "*.pl" -or -name "*.pm" \)
find / -type f | xargs grep -nH 'curl'
# print the word to find + the next 3 lines
grep -A 3 -i "theWordToFind" demo_text
find . -type f -name '*.sh' -print -exec grep -n gpg {} \;
# create a list of files
find . -print0 | xargs -r0 echo "$@"
# where am I
uname -a ;
# who am I
id ;
# when this is happening
date "+%Y.%m.%d %H:%M:%S" ;
# reboot ... !!! BOOM BOOM BOOM !!!
shutdown -r now
# shutdown the whole system
shutdown -f -s 00
#how-to kill a process
ps -aux | grep $proc_to_find
pidof $prod_to_find
kill -9 $proc_to_find
# which processes are listening on my system
netstat --tcp --listening --programs
netstat --tcp
netstat --route
#monitoring commands
# show the top processes
top
# now press Shift + o, and choose the field to sort by
# running processes status
ps -auxw | less
ps -ef | less
#List all currently loaded kernel modules
lsmod | less
#Displays the system's current runlevel.
/sbin/runlevel
# get the Processes attached to open files or open network ports:
lsoff | less
# monitor the virtual memory
vmstat
# show the free memory
free -m
# check memory usage
egrep --color 'Mem|Cache|Swap' /proc/meminfo
#what cpu am a running
less /proc/cpuinfo
#Display/examine memory map and libraries (so). Usage: pmap pid
ps -aux | grep $MyProcToPMap
pmap $MyprocToPMapPID
#how-to sort output by a delimited by single delimiter column
# in this example the - char is used for delimiter , the output is
# by their sending sequence , use proper file naming convention files
# ls -1 gives us:
# fileBeginningTillFirstDelimiter-TheColumnToSortBy-TheRestFromTheFileNameDelimiter
ls -1 | awk -F1 'BEGIN {FS="-"};{print $2 "¤" $1 "-" $2 "-" $3 }' | sort -nr | cut -d ¤ -f 2,5
# the same approach with perl
ls -1 | perl -p -i -e 's/^([^\-]*)(\-)([^\-]*)(\-)([^\-]*)/$3¤$1.2.8$4$5/g' | sort -nr | cut -d ¤ -f 2,5
# how-to use sftp with remoteUserName having publicIdentity of PublicIdentityUserName
sftp -v -o "IdentityFile /var/www/.ssh-id/PublicIdentityUserName" \
-o "UserKnownHostsFile /var/www/.ssh-id/known_hosts" remoteUserName@ServerHostNameOrIpd
ssh -v -o ServerAliveInterval 300 -o ServerAliveCountMax 1
# ==================================================================
# START Jobs control
# start some very long lasting command
find / -name '*.crt' | less
# now press Ctrl + Z
# the terminal says "Jobs stopped"
# now check the open jobs
jobs
# you should see something like
# [1]+ Stopped find / -name '*.crt' | less
# now put the job in the background and start working on something else by Ctrl + Z
bg 1
# run the next command
# how-to copy file via scp by using specificy identity
scp -v -o "IdentityFile /home/userName/.ssh/id_rsa" /data/path/dir/* \
userName@ServerHostName.Domain.com:/Server/Target/Dir/
# now again stop the job first by Ctrl + Z
# check again the running jobs
jobs
# use should see the both of the jobs started
# now put the first on in the forground
fg 1
# Repeat that several times untill you get it ; ) !!!
# start command in the background
command1 &
# how-to redirect STDERR STDOUT to log file
sh $script.sh | tee 2>&1 $log_file
# how-to start a separate shell
( command &) &
# get the STDERR and STDOUTPUT
output=$(command 2>&1)
# how-to detach an already started job from the terminal
jobs
disown -h %1
# how-to start
nohup log_script.sh &
# run a proc every 2 seconds
watch -n 2 "$cmd_to_run"
# END Jobs control
# ==================================================================
nicedate=`date +%Z-%Y%m%d%H%M%S`
# kill a process by name
ProcNameToKill=listener-nat_filter_caller.sh
# ps -ef | grep wget | perl -ne 'split /\s+/;print "kill $_[7] with PID $_[1] \n";`kill -9 $_[1];`'
ps -ef | grep $ProcNameToKill | grep -v "grep $ProcNameToKill" | \
perl -ne 'split /\s+/;print "kill $_[7] with PID $_[1] \n";`kill -9 $_[1];`'
# how-to display human readable file sizes on systems with stupid du
# of course you would have to have perl next_line_is_templatized
find $dir -type f -exec du -k {} \; | \
perl -ne 'split /\s+/;my $SizesInMegs=$_[0]/1024; \
printf ( "%10d %10s \n" , "$SizesInMegs" , "MB $_[1]")' | sort -nr
export dir=/
echo sizes in MB
find $dir -type f -exec du -k {} \; | \
perl -ne 'split /\s+/;my $SizesInMegs=$_[0]/1024; \
printf ( "%10d %-100s \n" , "$SizesInMegs" , "$_[1]")' | sort -nr | more
#who has been accessing via ssh
for file in `find /var/log/secure* | sort -rn` ; do grep -nHP 'user' $file ; done; | less
#print files recursively
dir=/opt/
clear;find $dir -type f -exec ls -alt --time-style=long-iso --color=tty {} \; | \
perl -ne 'split(/\s+/);printf ( "%10s %2s %-20s \n" , "$_[5]", "$_[6]", "$_[7]") ; ' | sort -nr
#how-to print relative file paths to /some/DirName with perl one liner
find /some/DirName -type f | perl -ne 'split/DirName\//;print "$_[1]" '
# see nice dir recursively listing newest first
dir=/tmp
find $dir -name '*.tmp' -exec ls -alt --time-style=long-iso --color=tty {} \; | \
perl -ne 'split/\s+/;print "$_[5] $_[6] $_[7] \n" ;' | sort -nr | less
# how-to sort files based on a number sequence in their file names
# list dir files , grap a number from their names , print with NumberFileName, sort , \
# print finally the names without the Number but sorted
ls -1 | perl -ne 'm/(\d{8})/; print $1 . $_ ;' | sort -nr | perl -ne 's/(\d{8})//;print $_'
# START === how-to implement public private key authentication
# create pub priv keys on server
# START copy
ssh-keygen -t rsa
# copy the rsa pub key to the ssh server
scp ~/.ssh/id_rsa.pub $ssh_user@$ssh_server:/home/$ssh_user/
# STOP copy
# Hit enter twice
# START copy
cat id_rsa.pub >> ~/.ssh/authorized_keys
cat ~/.ssh/authorized_keys
chmod 0600 ~/.ssh/authorized_keys
ls -al ~/.ssh/authorized_keys
rm -fv ~/id_rsa.pub
# STOP COPY
# START copy
ssh-keygen -t dsa
# STOP copy
# Hit enter twice
# START copy
cat id_dsa.pub > ~/.ssh/authorized_keys2
cat ~/.ssh/authorized_keys2
chmod 644 ~/.ssh/authorized_keys2
# STOP COPY
# STOP === how-to implement public private key authentication
# show me a nice calendar
cal -m -3
# START === how-to enable port forwarding or tunnelling
export local_port=6000
export remote_port=6000
export ssh_user=type_here_ssh_user
export ssh_server=type_here_the_hostname
export db_server=type_here_the_db_hostname
#[-L [bind_address:]port:host:hostport]
ssh -L localhost:$local_port:$db_server:$remote_port $ssh_user@$ssh_server
# STOP === how-to enable port forwarding or tunnelling
# START === cron scheduling
#edit the crontab
crontab -e
# view the crontab
crontab -l
# * * * * * command to be executed
# - - - - -
# | | | | |
# | | | | +- - - - day of week (0 - 6) (Sunday=0)
# | | | +- - - - - month (1 - 12)
# | | +- - - - - - day of month (1 - 31)
# | +- - - - - - - hour (0 - 23)
# +--------------- minute
# STOP === cron scheduling
#how-to limit the resources of the current session
help ulimit
nameTerminal $USER@`hostname`_ON_`pwd`__at__`date +%Y-%m-%d_%H:%M:%S`
# how-to send via e-mails the files of a dir with mailx
export dir=`pwd`
export attachments=$(find $dir -type f| perl -ne 'print "-a $_"'| xargs)
echo $attachments | mailx $attachments -s "$dir files" $MyEmail
mailx $(find $dir -type f| perl -ne 'print "-a $_"'| xargs) -s "$fir files" $MyEmail < `echo $(find $dir -type f| perl -ne 'print "-a $_"'| xargs)`
# change user password expiry information
for usr in "$userlist"; do sudo passwd $usr; sudo chage -E -1 -M -1 $usr; sudo chage -d0 $usr; done
#how-to check the file encoding
file_encoding=$(file -bi $file | sed -e 's/.*[ ]charset=//')
# Purpose:
# to provide a simple cheat sheet for most of the Linux related commands
# usefull web sources: http://www.cyberciti.biz
# how-to add new repository to yum
yum-config-manager --add-repo http://www.example.com/example.re
#how-to view installed packages with yum on RH
yum list installed | less
yum clean all
yum -y install perl
# update all but the linux kernel packages
yum -y --exclude=kernel\* update
/nz/kit/sbin/sendMail -dst first.last@company.com -msg "subject line" -bodyTextFile $outfile -removeFile
# start putty with preloaded session on windowz
cmd /c start /max putty -load username@hostname
#how-to install only specific package from cygwin via cmd
setup-x86_64.exe -n -q -s http://cygwin.mirror.constant.com -P %package_name%
c=0
cat "$list_file" | { while read -r jira_issue ; do c=$((c+1)) ; test $c -eq 5 && sleep $c && export c=0 ; ( sh /maintenance/ip/sfw/sh/jira --action progressIssue --issue $jira_issue --step 41 )& done }
# how-to enable pw auth on apache
pw_file=/var/www/html/maint/.htpasswd
user=mmt
htpasswd -c $pw_file $user
#how-to change the access and mofication timestamp
ts='201401181205.09'
touch -a -m -t "$ts" "$file"
# how-to install packages on ubuntu
apt-get -y install $package_name
# howto install packages on red-hat
yum install $package_name
#v1.9.5 how-to use text editor for longer command typing
set EDITOR=vim
#Ctrl+X,E
#v1.9.5 - how-to get variations by curly expansions
echo {A,B,C}{0,1,3}
#useful sources - hint: google site:<site>
#http://www.cyberciti.biz
#http://www.yolinux.com/TUTORIALS/LinuxTutorialSysAdmin.html#MONITOR
#http://www.commandlinefu.com/commands/browse/sort-by-votes
#http://wiki.bash-hackers.org/
#
#==========================================================
# VersionHistory
#==========================================================
# 1.9.5 --- 2014-23-04 22:37:07 --- ysg --- Ctrl+X,E trick
#
# eof file:linux-cheat-sheet
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