check if directory exists and delete in one command unix - unix

Is it possible to check if a directory exists and delete if it does,in Unix using a single command? I have situation where I use ANT 'sshexec' task where I can run only a single command in the remote machine. And I need to check if directory exists and delete it...

Why not just use rm -rf /some/dir? That will remove the directory if it's present, otherwise do nothing. Unlike rm -r /some/dir this flavor of the command won't crash if the folder doesn't exist.

Assuming $WORKING_DIR is set to the directory... this one-liner should do it:
if [ -d "$WORKING_DIR" ]; then rm -Rf $WORKING_DIR; fi
(otherwise just replace with your directory)

Try:
bash -c '[ -d my_mystery_dirname ] && run_this_command'
This will work if you can run bash on the remote machine....
In bash, [ -d something ] checks if there is directory called 'something', returning a success code if it exists and is a directory. Chaining commands with && runs the second command only if the first one succeeded. So [ -d somedir ] && command runs the command only if the directory exists.

Here is another one liner:
[[ -d /tmp/test ]] && rm -r /tmp/test
&& means execute the statement which follows only if the preceding
statement executed successfully (returned exit code zero)

I recommend opening documentation of rm command.
If open then you will see that there is a
-f flag does what you want. Example: rm -f -R ./my_folder

Related

How do I reset and put the zshrc file back to default?

/Users/ello/.zshrc:source:3: no such file or directory:
/Users/ello/Projects/config/env.sh
Ello-MacBook-Pro% /Users/ello/.zshrc:source
zsh: no such file or directory: /Users/ello/.zshrc:source
Ello-MacBook-Pro% /Users/ello/.zshrc
zsh: permission denied: /Users/ello/.zshrc
Ello-MacBook-Pro%
This has been happening, after I foolishly edited the .zshrc file. All that remains in the file now, after attempting to reset the shell, is this:
# Created by newuser for 5.3.1
# Add env.sh
How do I undo everything, reinstall zsh, or remake the .zshrc file?
This is on macOS Sierra.
Edit: I reinstalled oh-my-zsh, leading to this message:
ain() {
# Use colors, but only if connected to a terminal, and that terminal
# supports them.
if which tput >/dev/null 2>&1; then
ncolors=$(tput colors)
fi
if [ -t 1 ] && [ -n "$ncolors" ] && [ "$ncolors" -ge 8 ]; then
RED="$(tput setaf 1)"
GREEN="$(tput setaf 2)"
YELLOW="$(tput setaf 3)"
BLUE="$(tput setaf 4)"
BOLD="$(tput bold)"
NORMAL="$(tput sgr0)"
else
RED=""
GREEN=""
YELLOW=""
BLUE=""
BOLD=""
NORMAL=""
fi
# Only enable exit-on-error after the non-critical colorization
stuff,
# which may fail on systems lacking tput or terminfo
set -e
CHECK_ZSH_INSTALLED=$(grep /zsh$ /etc/shells | wc -l)
if [ ! $CHECK_ZSH_INSTALLED -ge 1 ]; then
printf "${YELLOW}Zsh is not installed!${NORMAL} Please install zsh
first!\n"
exit
fi
unset CHECK_ZSH_INSTALLED
if [ ! -n "$ZSH" ]; then
ZSH=~/.oh-my-zsh
fi
if [ -d "$ZSH" ]; then
printf "${YELLOW}You already have Oh My Zsh installed.${NORMAL}\n"
printf "You'll need to remove $ZSH if you want to re-install.\n"
exit
fi
# Prevent the cloned repository from having insecure permissions.
Failing to do
# so causes compinit() calls to fail with "command not found:
compdef" errors
# for users with insecure umasks (e.g., "002", allowing group
writability). Note
# that this will be ignored under Cygwin by default, as Windows ACLs
take
# precedence over umasks except for filesystems mounted with option
"noacl".
umask g-w,o-w
printf "${BLUE}Cloning Oh My Zsh...${NORMAL}\n"
hash git >/dev/null 2>&1 || {
echo "Error: git is not installed"
exit 1
}
# The Windows (MSYS) Git is not compatible with normal use on cygwin
if [ "$OSTYPE" = cygwin ]; then
if git --version | grep msysgit > /dev/null; then
echo "Error: Windows/MSYS Git is not supported on Cygwin"
echo "Error: Make sure the Cygwin git package is installed and is
first on the path"
exit 1
fi
fi
env git clone --depth=1 https://github.com/robbyrussell/oh-my-zsh.git
$ZSH || {
printf "Error: git clone of oh-my-zsh repo failed\n"
exit 1
}
printf "${BLUE}Looking for an existing zsh config...${NORMAL}\n"
if [ -f ~/.zshrc ] || [ -h ~/.zshrc ]; then
printf "${YELLOW}Found ~/.zshrc.${NORMAL} ${GREEN}Backing up to
~/.zshrc.pre-oh-my-zsh${NORMAL}\n";
mv ~/.zshrc ~/.zshrc.pre-oh-my-zsh;
fi
zsh itself does not have a default user configuration. So the default ~/.zshrc is actually no ~/.zshrc.
But as you tagged the question with oh-my-zsh I would assume that you want to restore the default oh-my-zsh configuration. For this it should be sufficient to copy templates/zshrc.zsh-template from your oh-my-zsh installation path, usually ~/.oh-my-zsh:
cp ~/.oh-my-zsh/templates/zshrc.zsh-template ~/.zshrc
You may want to backup your current ~/.zshrc beforehand. Although it may have some problems now, you still might want to look up some settings once you reverted to default.
There is no such thing as "default". The best you can do, is check if your system has /etc/skel/.zshrc. If yes copy that into your home.
When you log in first time, your home is populated with everything from /etc/skel.
My dumass decided to just put a crash command into the zsh file. Now when I open the terminal, it just kernel panics. so I just deleted the config file using rm -f ~/.zshrc* and by default, it just got replaced with another copy. So good luck.
You can copy .zshrc template from
https://github.com/ohmyzsh/ohmyzsh/blob/master/templates/zshrc.zsh-template
And copy and paste all content in to ~/.zshrc
[MS Windows Friendly Solution - If terminal(using vim editor) steps are confusing]
Actually, there is no default .zshrc file, but if you need to edit is as a simple notepad, do these:
Goto /Users/ Folder via Finder App.
Click Shift + Command + . (Dot) to view hidden system files.
Look on .zshrc file, double click to open, then it will open in a notepad(TextEdit.app) in default.
Clear whichever lines to be removed.
Retype/Edit the file as per the Paths to be added.
Hit Command + s to save and exit.
Make it your default shell using this command:
chsh -s $(which zsh)

Check if file exists or not in KORN Shell

I want to check if file exists are not in a Korn shell, but not able to get a proper documentation for that. I have the following code that checks if file exists and is of size zero. If the file size is more than zero it returns false.
if [[ ! -s ${abs_file_name} ]]
I need a list of possible options (like -s, -e, -x, etc like in the above example) with description to check if file exists in KORN shell, NOT BASH shell.
You can check if a node exists with
if [ -e "${abs_file_name}" ]
You can check if a node is a file.
if [ -f "${abs_file_name}" ]
This does something dumb if abs_file_name resolves to a symlink to a file.
Also: -d for directory, -r for you can read it, -x for executable.

Unix script changing directory

I am in root directory, i am creating a script that will take me from root > Home > Logs and inside logs delete 3 log files.
Script will check if they exist, if YES it will delete it.
I am facing some syntax problems if you could help.
Thanks
My code:
#!/bin/sh
cd Home/Log
if [ -e error1.log ]
then
rm error1
fi
if [ -e error2.log ]
then
rm error1
fi
if [ -e error3.log ]
then
rm error1
fi
when i execute the file in root using ./delete here is what is am getting as errors:
$ ./delete
: No such file or directoryme/Log
./delete: line 14: syntax error near unexpected token `fi'
I am in root directory
When writing a script, it's almost always better not to assume things like that. If you know where the files are and it's not important that they're somewhere relative to what happens to be your current working directory, just name them.
Here are three ways you could accomplish what you want safely.
#!/bin/sh
dir=/Home/Log
rm -f ${dir}/error1.log ${dir}/error2.log ${dir}/error2.log
or
#!/bin/sh
dir=/Home/Log
rm -f ${dir}/error{1,2,3}.log
or
#!/bin/sh
set -e
cd /Home/Log && rm -f error1.log error2.log error2.log
For anything nontrivial, set -e is your friend. In your example, nothing happens later in the script. What you don't want is to keep going thinking you've changed directories, but haven't, and wind up scribbling somewhere you didn't intend. Many have lost much that way.

Removing files - Silent failure issue

In a Unix environment, I have a bash script that removes some files:
rm -f foo bar* baz*
My problem: not always the wildcard returns any result. And as a result of that, I fail to remove even 'foo' which always exists. The output written is "rm: No match".
A simple workaround would be to split the command:
rm -f foo
rm -f bar*
rm -f baz*
But it's a bad solution.
No it should work. Which shell is used ? Is rm an internal version or an external ? (Try /bin/rm instead to ensure the external version). You may have some shell option set that prevent you to execute the command in that case (this may depend on your shell).

How to always have the same current directory in VIm and in Terminal?

I would like to my terminal current directory follows my VIM one.
Example:
In TERMINAL:
> pwd
=> /Users/rege
> vim
Then in VIM
:cd /Users/rege/project
<Ctrl-z>(for suspend)
In terminal
> pwd
=> /Users/rege/project
I`m using MacOS, zsh, tmux.
I need this because when Im trying to use tags in VIM, tags are check in project from my terminal directory not vim one.
So I need to change terminal current directory always when I change VIM current directory.
What kind of command do you issue in your shell after you suspend Vim? Isn't Vim's :!command enough?
With set autochdir, Vim's current directory follows you as you jump from file to file. With this setting, a simple :!ctags -R . will always create a tags file in the directory of the current file.
Another useful setting is set tags=./tags,tags;$HOME which tells Vim to look for a tags file in the directory of the current file, then in the "current directory" and up and up until it reaches your ~/. You might modify the endpoint to suit your needs. This allows you to use a tags at the root of your project while editing any file belonging to the project.
So, basically, you can go a long way without leaving Vim at all.
If you really need to go back to the shell to issue your commands, :shell (or :sh) launchs a new shell with Vim's current directory. When you are done, you only have to $ exit to go back to Vim:
$ pwd
/home/romainl
$ vim
:cd Projects
:sh
$ pwd
/home/romainl/Projects
$ exit
In bash or zsh and on Unix you can do this: current working directory of the process is represented in /proc/{PID}/cwd as a symlink to a real directory. Speaking about zsh the following code will do the job:
function precmd()
{
emulate -L zsh
(( $#jobstates == 1 )) || return
local -i PID=${${${(s.:.)${(v)jobstates[1]}}[3]}%\=*}
cd $(readlink /proc/$PID/cwd)
}
. Note: with this code you won’t be able to pernamently switch directories in terminal anymore, only in vim or for duration of one command (using cd other-dir && some command).
Note 2: I have no idea how to express this in bash. The straightforward way is to get PIDs of all children of the shell (using ps --ppid $$ -o CMD), filter out the ps process (it will be shown as a child as well), check that there is only one other child and use its PID like in the last line above. But I am pretty sure there is a better way using some shell builtins like I did with zsh’s $jobstates associative array. I also don’t remember what is the analogue of precmd in bash.
Another idea would be making vim save its current directory into some file when you do <C-z> and make shell read this in precmd:
" In .vimrc:
function s:CtrlZ()
call writefile([fnamemodify('.', ':p')], $CWDFILE, 'b')
return "\<C-z>"
endfunction
nnoremap <expr> <C-z> <SID>CtrlZ()
# In .zshrc
function vim()
{
local -x CWDFILE=~/.workdirs/$$
test -d $CWDFILE:h || mkdir $CWDFILE:h
vim $#
}
function precmd()
{
local CWDFILE=~/.workdirs/$$
test -e $CWDFILE && cd "$(cat $CWDFILE)"
}
. It should be easier to port above code to bash.
you can open a new terminal like this
:!xterm -e bash -c "cd %:p:h;bash" &
actually I write this in my .vimrc
nmap <F3> :!xterm -e bash -c "cd %:p:h;bash" &<CR> | :redraw!
For bash users coming by:
Vim: Save pwd at <c-z> (with map and getpwd()).
Bash: Before prompt command, goto directory indicated by vim with PROMPT_COMMAND.
.bashrc
PROMPT_COMMAND='read -r line 2>/dev/null </tmp/cd_vim'\
'&& > /tmp/cd_vim && cd ${line##\r};'$PROMPT_COMMAND
vimrc
function! s:CtrlZ() call writefile([getcwd(),''], '/tmp/cd_vim', 'b')
return "\<C-z>"
endfunction
nnoremap <expr> <C-z> <SID>CtrlZ()
This is ZyX answer edited for bash https://stackoverflow.com/a/12241861/2544873

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