Check out this site, excellent reference for any shell script syntax.
Monthly Archives: June 2012
Mojolicious – Perl real-time web framework
Mojolicious – Perl real-time web framework
Awesome, super easy to use Perl web framework, check it out!
UNIX-1.11 zip, basename, mktemp, script and rcs commands
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zip -r filename.zip file1 file2 file3 – zip and compress files, recursively
unzip filename.zip – unzip a zip file
rmdir dirname – remove empty directory
basename fullpath – returns the file or directory name
dirname fullpath – returns the directory
mktemp – creates a temporary file and outputs temp filename
factor number – list the factors of a number
script -a script.out – starts recording your output screen, ctrl+D to stop recording
kill %% – kills previous command
sudo apt-get install rcs – to install linux revision control system (RCS)
mkdir RCS – create a directory called RCS to store all versions of file
ci script.sh – checks in a file, file is not readable until checked out
ci -u script.sh – checks in a file, file is visible for others to read
co -l script.sh – checks out a file, holds the lock.
co -lr1.1 script.sh – checks out a version of file, holds the lock
rcsdiff script.sh – compares current file with latest checked in version
rcsdiff -r1.1 -r1.2 script.sh – compares version 1.1 and 1.2
which command – tells you where such command resides in
locate keyword – searches for files or paths that contains keyword (that are accessible to you)
Tips for customizing your command prompt
Tips for customizing your command prompt
Check out this webpage for complete list of available command prompt customization, you gonna love your new command prompt :)
UNIX-1.10 Customize Command Prompt
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set -o vi – puts your command prompt into VI mode, allows you to execute VI commands
/command – search for command history, n for next match found, N for previous match found
PS1 – variable that holds text of your prompt
PS1=”\H” – displays host name
PS1=”\s” – name of shell
PS1=”\u” – current username
PS1=”\w” – current working directory
PS1=”\@” – current time
PS1=”[\\u@\\H \\W \\@]\\$” – try this
PS1=”\e[x;ym$PS1\e[m” – \e[ starts the color mode, x;ym specifys color, \e[m ends color mode. x;y can be 0;30 to 0;37
case $(id -u) in
0) PS1=”${PS1}# “;;
*) PS1=”${PS1}$ “;;
esac
alias name=”command -options” – creating alias/shortcut commands
alias vi=’vim’
alias ls=’ls -F’
alias ll=’ls -l’
alias la=’ls -la’
alias cp=’cp -ip’
alias mv=’mv -i’
UNIX-1.9 .bash_profile vs .bashrc
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sed – stands for “stream editor”, not “special editor”
umask 022 – user creation mask, 022 = rwxr-xr-x
/etc/profile – system wide profile, set by root
Weekend’s Plan
At least 2 new videos on UNIX and 2 new videos on Perl. Stay tuned!
UNIX-1.8 ps, netstat, kill, pidof, fuser, awk commands
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ps -fu username – displays all processes started by user
ps -ef – display all processes running
ps -ef | grep ‘pname’ – look for specific process
netstat -t – see all tcp connections
netstat -an – see all network connections
netstat -c – netstat will execute every second
netstat -p – display processes that use these connections
kill pid – kills process by pid
kill -9 pid – force kill process by pid
& – execute process in background
free – show memory usage, alternatively use top
pidof command – shows process id for running process/command
fuser -vu dir – displays all processes that are using dir, along with owner id of processes
echo “hello world” | awk ‘{ print length($1) }’ – prints length of field
echo “hello world” | awk ‘{ print substr($1, 3) }’ – prints llo, substring function
echo “hello world” | awk ‘{sub(regex, replacement); print}’ – replace pattern on line and print
echo “HELLO world” | awk ‘{ print tolower($1) }’ – lower case field 1
echo “hello world” | awk ‘{ print toupper($1) }’ – upper case field 1
UNIX-1.7 Find Command
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find . -iname ‘regex’ – find filenames that match regex, case insensitive
find . -mtime +2 – find files that were modified 2 days ago or older
find . -mtime -2 – find files that were modified within past 2 days
find . -ctime +2 – find files that were created 2 days or older
find . -atime +2 – find files that were accessed 2 days or older
find . -cmin +30 – find files that were created 30 minutes ago or older
find . -mmin +30 – find files that were modified 30 minutes ago or older
find . -empty – find empty files or directory
find . -executable – find files that are executable by user
find . -readable – find files that are readable by user
find . -writable – find files that are writable by user
find . -size filesize – find files that have specified filesize (c = byte, k = kb, M = Mb, G = Gb)
find . -type filetype – find by file type (d = directory, f = file, l = link)
find . -user username – find files owned by user
find . -group groupname – find files that belong to specific group
find . -name ‘regex’ -delete – remove files that match regex
find . -name ‘regex’ -exec command – execute command on files found
find . -name ‘regex’ -ok command – same as -exec, but prompts for user’s input
UNIX-1.6 grep, useradd, usermod commands
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last -10 username – get last 10 logins of specific user
passwd – change password
diff -y file1 file2 – find differences between 2 files
grep ‘regex’ file – search for pattern
grep -i ‘regex’ file – case insensitive search
grep -P ‘regex’ file – full support of Perl regex
grep -e ‘regex1’ -e ‘regex2’ file – search for multiple patterns
grep -v ‘regex’ file – inverse of search pattern (return non-matching lines)
grep -n ‘regex’ file – display line number with search result
grep -B4 ‘regex’ file – also display 4 lines before match
watch -n5 command – executes command every 5 second
adduser username – add a new user
usermod username -d /home/newhome – change home for new user
usermod username -d /home/newhome -m – change and move home content to a new home
usermod username -e 2022-05-11 – set account expiration date
usermod username -g group_name – set user group name/id
usermod username -l new_username – change username for user
usermod username -p new_password – change password for user
usermod username -s shell_name – change default shell for user
sudo -u username -i – run future commands as another user