Ctrl + A Go to the beginning of the line you are currently typing on Ctrl + E Go to the end of the line you are currently typing on Ctrl + L Clears the Screen, similar to the clear command Ctrl + U Clears the line before the cursor position. If you are at the end of the line, clears the entire line. Ctrl + H Same as backspace Ctrl + R Let’s you search through previously used commands Ctrl + C Kill whatever you are running Ctrl + D Exit the current shell Ctrl + Z Puts whatever you are running into a suspended background process. fg restores it. Ctrl + W Delete the word before the cursor Ctrl + K Clear the line after the cursor Ctrl + T Swap the last two characters before the cursor Esc + T Swap the last two words before the cursor Alt + F Move cursor forward one word on the current line Alt + B Move cursor backward one word on the current line Tab Auto-complete files and folder names
9.24.2013
Bash Keyboard Shortcuts
9.19.2013
Vi Text Editor My Frequently Used Commands
h move cursor one character to left
j move cursor one line down
k move cursor one line up
l move cursor one character to right
w move cursor one word to right
b move cursor one word to left
0 move cursor to beginning of line
$ move cursor to end of line
nG move cursor to line n
1G move cursor to 1st line
G move cursor to last line
control-f scroll forward one screen
control-b scroll backward one screen
gx jump to method definition
zi switch folding on or off
za toggle current fold open/closed
zc close current fold
zR open all folds
zM close all folds
zv expand folds to reveal cursor
i insert to left of current cursor position (end with ESC)
a append to right of current cursor position (end with ESC)
dw delete current word (end with ESC)
cw change current word (end with ESC)
r change current character
~ change case (upper-, lower-) of current character
dd delete current line
D delete portion of current line to right of the cursor
x delete current character
dgg delete current line to the top of the file
jdG delete all lines below current line
ma mark currrent position
d`a delete everything from the marked position to here
`a go back to the marked position
p dump out at current place your last deletion (``paste'')
u undo the last command
. repeat the last command
J combine (``join'') next line with this one
:w write file to disk, stay in vi
:q! quit VI, do not write file to disk,
ZZ write file to disk, quit vi
:r filename read in a copy of the specified file to the current
buffer
/string search forward for string (end with Enter)
?string search backward for string (end with Enter)
n repeat the last search (``next search'')
N repeat the last search backward
/\cstring case insensitive prepend with \c
:s/s1/s2 replace (``substitute'') (the first) s1 in this line by s2
:lr/s/s1/s2/g replace all instances of s1 in the line range lr by s2
(lr is of form 'a,b', where a and b are either explicit
line numbers, or . (current line) or $ (last line)
:map k s map the key k to a string of vi commands s (see below)
:abb s1 s2 expand the string s1 in append/insert mode to a string
s2 (see below)
% go to the "mate," if one exists, of this parenthesis
or brace or bracket (very useful for programmers!)
:%s/foo/bar/g replace every 'foo' with a 'bar'
:!command execute a command from vi
:%!perltidy format perl code using perltidy from within vi
:%!perltidy -l=0 ignore line length
:noh remove search highlighting
:sp to split window horizontally
:vsp to split window vertically
<ctrl-w>h|j|k|l to navigate between split windows
<ctrl-w>q to quit split window
Comment/Uncomment:
Press Ctrl+V and go down until the last commented line and press x, that will delete all the # characters vertically.
For commenting a block of text is almost the same: First, go to the first line you want to comment, press Ctrl+V, and select until the last line. Second, press Shift+I, then #, then Esc.
Indent several lines at once:
Press Ctrl+V and go down until the last line to be indented, press Shift+>
Cut/Copy and Paste:
Position the cursor where you want to begin cutting.
Press v (or upper case V if you want to cut whole lines).
Move the cursor to the end of what you want to cut.
Press d to cut or y to copy.
Move to where you would like to paste.
Press P to paste before the cursor, or p to paste after.
Copy and paste can be performed with the same steps, only pressing y instead of d in step 4.
The name of the mark used is related to the operation (d:delete or y:yank).
9.17.2013
Linux Cheat Sheet
1. Find Out Linux Distribution Name and Version:
$ cat /etc/∗-release Red Hat Enterprise Linux Server release 5 (Tikanga)2. Use scp (Cygwin) to transfer files:
>scp -r [user_name]@[host_name or host_ip]:[Path to your directory] [target_path_dir] >scp -r root@server.domain.com:/tmp/example.zip . >scp -r user@your.server.example.com:/path/to/foo /home/user/Desktop/from local to remote server:
>scp file* root@server.domain.com:/tmp3. Copy files from a linux server to another linux server
rsync -auv -e ssh --progress source_folder/ useraccount@machine.whatever.com:/destination_folder/4. Find files using 'find'
#find files from current directory and subdirectories that matches mon*
$ find . -name mon\*
#find files from current directory and subdirectories displaying the full path
$ find `pwd` -name koala\*
#or
$ find `pwd` | grep koala
#find files older than 90 days and move to another directory
$ find /home/perf-builder/deploy -maxdepth 1 -mtime +90 -type f -exec mv "{}" /perflogs/deploy_package_archive/ \;
#find files that are writable by anyone
$ find -maxdepth 1 -type f -perm /222
#find files that are writable by their owners
$ find -maxdepth 1 -type f -perm /200
5. Delete environment variable
$ env | grep rvm OLDPWD=/home/samdc/.rvm $ unset OLDPWD6. Set environment variable
$ export PATH=/usr/lib/lightdm/lightdm:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games7. Monitor log file as the file grows using tail
$ tail -f /home/sammydc/logs/request.log8. Search a directory for files containing certain string
$ grep -r "192.168.1.5" /etc/ $ grep -E "whatever" -r . - recursive on current dir and subdirs # multi-line grep $ grep -Ezl "FC_count\s+2.*autoselect\s+yes.*client_os_version_linux\s+CentOS 6.5.*fc_switch\s+ls-dur3-mds2.*motherboard_product_name\s+.*C240.*use_for_group\s+Perf" *.cfg # grep from different directories from July 21 – July 28 grep 'caught exception: ERROR' /mnt/perfresults/*/logs/2016072[1-8]_*/controller_log9. This will show process id, user, command and arguments:
$ ps -e -o "pid,user,comm,args"10. Cat a bunch of files at once
$ for f in /var/log/*.log; do cat $f; done11. Iterate thru a list and apply operation
Copy a file to multiple destination
$ for FILE in {544..579}; do cp perf-c440 perf-c$FILE; done
Ping several clients
$ for CLIENT in client1 client2 client3; do ping $CLIENT -c2; done
12. Filter using grep with regex
$ ps -efw | grep -E '5\.5.*dd670'13. List directories up to 3 levels down, then filter
$ ls -d ./*/*/* | grep 41604114. Get number of cpus
$ cat /proc/cpuinfo | grep processor | wc -l15. Get memory info
$ cat /proc/meminfo16. Get disks info
$ cat /proc/partitions $ df -H17. How to determine biggest directories/files occupying disk
$ df Filesystem 1K-blocks Used Available Use% Mounted on /dev/sda5 26011288 24703036 0 100% / /dev/sda1 202219 63562 128217 34% /boot $ df -BG (in GigaBytes) Filesystem 1G-blocks Used Available Use% Mounted on /dev/dd_dg0_0p15 2G 2G 1G 68% / /dev/dd_dg0_0p14 5G 4G 2G 72% /ddr /dev/dd_dg0_0p13 30G 30G 0G 100% /ddr/var $ du -a /home | sort -n -r | head -n 10 14259824 /home 14259052 /home/delacs 14259048 /home/delacs/scheduler 14256188 /home/delacs/scheduler/ctl 9382796 /home/delacs/scheduler/ctl/run_request.log 3238172 /home/delacs/scheduler/ctl/resourcedb.log 1036148 /home/delacs/scheduler/ctl/requestdb.log 569516 /home/delacs/scheduler/ctl/update_resource_status.log 29492 /home/delacs/scheduler/ctl/www_index.log 2056 /home/delacs/scheduler/resources $ du -h /home | sort -h -r | head -n 10 (human readable form) $ du -ahx / | sort -h -r | head -n 50 (exclude mounted directories)18. Which processes take so much... Memory
$ ps -e -o pid,vsz,command | sort -n -r -k 2 | head -n 20 22796 345320 /usr/sbin/httpd 22799 344772 /usr/sbin/httpd 22907 344392 /usr/sbin/httpd 27749 242936 run_request_id_20140614_0800_mweb_dur 26515 217668 run_request_id_20140725_1738_mweb_dur 20061 217476 run_request_id_20140724_1600_mweb_dur 27748 215428 run_request_id_20140614_0800_mweb_dur ...CPU
$ ps -eo pcpu,pid,user,args | sort -k1 -r -n | head -20 8.8 9341 ioperf /usr/bin/python /home/ioperf/maestro-production/cloudapi/pcrun.py --noTty --logLevel DEBUG -s /tmp/tmpsap5Fn/cfg.json -w /tmp/tmpsap5Fn/cfg.json -r /tmp/tmpsap5Fn/cfg.json --scriptDir /home/ioperf/maestro-production --resultDirBase /data/maestro_prod/vsan-fio 7.0 29457 ioperf /usr/bin/python /home/ioperf/maestro-production/cloudapi/pcrun.py --noTty --logLevel DEBUG -s /tmp/tmpUvSJTh/cfg.json -w /tmp/tmpUvSJTh/cfg.json -r /tmp/tmpUvSJTh/cfg.json --scriptDir /home/ioperf/maestro-production --resultDirBase /data/maestro_prod/vsan-fio 0.4 8817 root /usr/bin/etserver --daemon --cfgfile=/etc/et.cfg ...19. Find files and delete them
The basic find command syntax is:
find dir-name criteria action
dir-name : - Defines the working directory such as look into /tmp/
criteria : Use to select files such as "*.sh"
action : The find action (what-to-do on file) such as delete the file.
$ find . -name ".nfs000000000006a8b200000062" -exec rm -rf {} \;
Options:
-name "FILE-TO-FIND" : File pattern.
-exec rm -rf {} \; : Delete all files matched by file pattern.
20. Echo string with a tab and append to end of a file
$ echo -e "autoselect\tyes" >> perf-c57621. Count number of directories
$ echo 201404*/ | wc22. Prepend contents of a file to another file
echo -e "`cat list.idx.forcopy`\n$(cat list.idx)" > list.idx23. Script execution time
$ time ./monitor_regression.pl ... Output ... real 0m57.766s user 0m0.444s sys 0m0.805s24. NFS mount
# mount -t nfs -o rw,nosuid,nodev,tcp,intr,nolock perfresultsSC:/backup /mnt/perfresultsSC/25. Time sync
# ntpdate time-server-name-or-ip26. Start process in background
$ ./my_process >std.txt 2>err.txt & $ ./my_process >std.txt 2>&1 & (both stdout and stderr goes to the same file) $ ./my_process >/dev/null 2>err.txt & (don't care about output, but stderr is recorded)27. Monitor CPU & Memory utilization
Get CPU utilization every 2 minutes and run forever $ mpstat -P ALL 120 > mpstat.log & Get memory utilization every 2 minutes in 2 weeks $ sar -r 120 10080 > sar.log &27. Put currently running process in the background
$ Ctrl+Z $ bg # be able to exit out of ssh connection without affecting the running process $ disown -h27. Memory usage of a process, units in MB
$ smem -P server.rb PID User Command Swap USS PSS RSS 2176 samdc ruby server.rb 0 240052 241281 24629628. Create a tarball
$ tar -cvf openssh.deploy.tar file1 file2 $ tar -zcvf archive-name.tar.gz directory-name $ tar -zcvf archive-name.tar.gz directory-name --remove-files (to remove original directory and files)29. View tarball contents
$ tar -tvf openssh.deploy.tar30. Extract tarball
$ tar -xvf openssh.deploy.tar31. Kill processes at once
$ ps -efw | grep rvc | grep '1 ' | awk '{print $2}' | xargs -I{} kill -9 {}
Safer...
$ ps -ewf | grep rvc | grep 10.92.81.163 | awk '{print $2}' | xargs -I{} kill -9 {}
30. Rename files in directory at once
$ for file in *.log; do mv "$file" "$file.old"; done31. How to remove all empty directories in a subtree
$ find ROOTDIR -type d -empty -delete e.g. $ find /mnt/maestro/maestro_prod/vsan-fio/15278 -type d -empty -delete32. Find out how much space files occupy in a directory
$ du -bch
9.13.2013
Ruby Gems Issues
Just a list of issues that I want to take note of while using ruby gems.
Encountered this problem when I tried to install Sinatra:
Encountered this problem when I tried to install Sinatra:
>gem install sinatra ERROR:Could not find a valid gem 'sinatra' (>= 0), here is why: Unable to download data from https://rubygems.org/ - SSL_connect returned=1 errno=0 state=SSLv3 read server certificate B: certificate verify failed (https://s3.amazonaws.com/production.s3.rubygems.org/latest_specs.4.8.gz)Solution is to specify the source explicitly and use http instead of https:
>gem install sinatra --source http://rubygems.org/
9.12.2013
MySQL Cheat Sheet
1. Connect to MySQL server in localhost
>mysql -u username -p password [databasename]2. Executing SQL Statements from a Text File
mysql> source c:\filename.sql3. Migrate database
# everything $ mysqldump -u [user] -p --opt mydb > mydb.sql # To export to file (data only) mysqldump -u [user] -p --no-create-info mydb > mydb.sql # To export to file (structure only) mysqldump -u [user] -p --no-data mydb > mydb.sql # To import to database mysql -u [user] -p mydb < mydb.sql
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