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 "${abs_file_name}" ]
This does something dumb if abs_file_name resolves to a symlink to a file.
Also: -d for directory, -r for you can read it, -x for executable.
Related
I'm relatively new to unix command line and I do not really understand what this command does:
[[ ! -e "$text_file" ]] || { echo "Error: I cannot overwrite '$text_file'." >&2;}
Does anyone have an idea?
First of all, it checks 2 conditions with logical OR || operator.
-e FILE - True if the FILE exists and is a file,
so the condition is negating the result of this check.
and then if this is false then it goes and prints the message and send that to stderr (>&2). If the first condition is true then second condition won't be evaluated (of course this default logical OR way of working)
In Unix-world, stdout is generally used when everything is working correctly and stderr is generally used to print messages when something goes wrong.
By default, stdout and stderr both print to your screen. The main difference is that the > and | operators catch stdout by default, but not stderr.
You can also check other things like below:
-r FILE - True if the FILE exists and is readable.
-w FILE - True if the FILE exists and is writable.
-x FILE - True if the FILE exists and is executable.
-d FILE - True if the FILE exists and is a directory.
-e FILE - True if the FILE exists and is a file, regardless of type (node, directory, socket, etc.).
-f FILE - True if the FILE exists and is a regular file (not a directory or device)
This checks a file for existence and the ! negates the expression
See a list of bash file testing
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
Im new to unix,I have search a lot of info but still don not how to make it in a bash
What i know is used this command ls -tr|xargs -i ksh -c "mv {} ../tmp/" to move file by file.
Now I need to make a script that sorts all of these files by system date and moves them into a directory, The first 1000 oldest files being to be moved.
Example files r like these
KPK.AWQ07102011.66.6708.01
KPK.AWQ07102011.68.6708.01
KPK.EER07102011.561.8312.13
KPK.WWS07102011.806.3287.13
-----------This is the script tat i hv been created-------
if [ ! -d /app/RAID/Source_Files/test/testfolder ] then
echo "test directory does not exist!"
mkdir /app/RAID/Source_Files/calvin/testfolder
echo "unused_file directory created!"
fi
echo "Moving xx oldest files to test directory"
ls -tr /app/RAID/Source_Files/test/*.Z|head -1000|xargs -i ksh -c "mv {} /app/RAID/Source_Files/test/testfolder/"
the problem of this script is
1) unix prompt a syntax erro 'if'
2) The move command is working but it create a new filename testfolder instead move to directory testfolder (testfolder alredy been created in this path)
anyone can gv me a hand ? thanks
Could this help?
mv `ls -tr|head -1000` ../tmp/
head -n takes the n first lines of the previous command (here the 1000 oldest files). The backticks allow for the result of ls and head commands to be used as arguments to mv.
I have a Unix batch script that copies the contents of one directory (call it dir A) to another (call it dir B).
Here is the copy statement I have currently.
cp -urL /path/to/dir/A /path/to/dir/B
However, this statement copies over hidden files.
How can I exclude any and all hidden files from being copied over?
Put star (*) in to copy but ignore hidden files
cp -urL -r /path/to/dir/A/* /path/to/dir/B
If using bash as your shell, unset the dotglob shell option.
From man bash
dotglob If set, bash includes filenames beginning with a '.' in the
results of pathname expansion.
#!/bin/bash
shopt -u dotglob
cp -urL /path/to/dir/A /path/to/dir/B
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