I'm working on a script that processes a folder and there is always one file in it I need to rename. The new name should be the parent directory name. How do I get this in a batch file? The full path to the dir is known.
It is not very clear how the script is supposed to become acquainted with the path in question, but the following example should at least give you an idea of how to proceed:
FOR %%D IN ("%CD%") DO SET "DirName=%%~nxD"
ECHO %DirName%
This script gets the path from the CD variable and extracts the name only from it to DirName.
You can use basename command:
FULLPATH=/the/full/path/is/known
JUSTTHENAME=$(basename "$FULLPATH")
You can use built-in bash tricks:
FULLPATH=/the/full/path/is/known
JUSTTHENAME=${FULLPATH##*/}
Explanations:
first # means 'remove the pattern from the begining'
second # means 'remove the longer possible pattern'
*/ is the pattern
Using built-in bash avoid to call an external command (i.e. basename) therefore this optimises you script. However the script is less portable.
Related
I know how to add values to the path variable, so my question is not how to use it.
Rather, I want to know how it works under the hood. When you type in the name of a program to execute, how does the system make use of PATH to find the matching program? How does it know when it finds a match?
for example...
when you set c:\python27\ into your environment path...
and you goto cmd, you are at c:\ and you type python
cmd knows to check the environment path which it will find c:\python27\ among others. then it looks for the command in each path listed in your environment paths
then executes the command if it finds it
simply the env path tells where to look for the command if it is not in the current directory
How can I find out (with Windows a batch command), if, for example, a variable starts with ABC?
I know that I can search for variables if I know the whole content (if "%variable%"=="abc"), but I want that it only looks after the beginning.
I also need it to find out where the batch file is located, so if there is a other command that reveals the file's location, please let me know.
Use the variable substring syntax:
IF "%variable:~0,3%"=="ABC" [...]
If you need the path to the batch file without the batch file name, you can use the variable:
%~dp0
Syntax for this is explained in the help for the for command, although this variable syntax extends beyond just the for command syntax.
to find batch file location use %0 (gives full patch to current batch file) or %CD% variable which gives local directory
I'm trying to use external script with variables, but in result I get only "no such file or directory".
1st.ksh
#!bin/ksh
PATHNAME = `dirname $0`
. $PATHNAME/2nd.ksh
Echo $EXTVAR
2nd.ksh
#!bin/ksh
EXTVAR=1
I tried to use "Source" instead of "." (Source $PATHNAME/2nd.ksh) and I get the same result.
To run script I'm using full path to the script - cygdrive/e/Folder/1st.ksh.
2nd.ksh in this path too (cygdrive/e/Folder/).
All rights was granted for both files (chmod u=rwx,g=rwx,o=rwx filename).
If I put files in cygwin home path (/home/username/) I have the same.
Please help to understand what I'm doing wrong.
Thanks in advance!
$() should be used in ksh instead of `` (link)
. should be user instead of source (link)
"=" must not be surrounded with spaces. You should write: PATHNAME=$(dirname $0)
you should be aware of case-sensitiveness: echo, source
When developing Pig scripts that use the STORE command I have to delete the output directory for every run or the script stops and offers:
2012-06-19 19:22:49,680 [main] ERROR org.apache.pig.tools.grunt.Grunt - ERROR 6000: Output Location Validation Failed for: 'hdfs://[server]/user/[user]/foo/bar More info to follow:
Output directory hdfs://[server]/user/[user]/foo/bar already exists
So I'm searching for an in-Pig solution to automatically remove the directory, also one that doesn't choke if the directory is non-existent at call time.
In the Pig Latin Reference I found the shell command invoker fs. Unfortunately the Pig script breaks whenever anything produces an error. So I can't use
fs -rmr foo/bar
(i. e. remove recursively) since it breaks if the directory doesn't exist. For a moment I thought I may use
fs -test -e foo/bar
which is a test and shouldn't break or so I thought. However, Pig again interpretes test's return code on a non-existing directory as a failure code and breaks.
There is a JIRA ticket for the Pig project addressing my problem and suggesting an optional parameter OVERWRITE or FORCE_WRITE for the STORE command. Anyway, I'm using Pig 0.8.1 out of necessity and there is no such parameter.
At last I found a solution on grokbase. Since finding the solution took too long I will reproduce it here and add to it.
Suppose you want to store your output using the statement
STORE Relation INTO 'foo/bar';
Then, in order to delete the directory, you can call at the start of the script
rmf foo/bar
No ";" or quotations required since it is a shell command.
I cannot reproduce it now but at some point in time I got an error message (something about missing files) where I can only assume that rmf interfered with map/reduce. So I recommend putting the call before any relation declaration. After SETs, REGISTERs and defaults should be fine.
Example:
SET mapred.fairscheduler.pool 'inhouse';
REGISTER /usr/lib/pig/contrib/piggybank/java/piggybank.jar;
%default name 'foobar'
rmf foo/bar
Rel = LOAD 'something.tsv';
STORE Rel INTO 'foo/bar';
Once you use the fs command, there a lot of ways to do this. For an individual file, I wound up adding this to the beginning of my scripts:
-- Delete file (won't work for output, which will be a directory
-- but will work for a file that gets copied or moved during the
-- the script.)
fs -touchz top_100
rm top_100
For a directory
-- Delete dir
fs -rm -r out
I came across this piece of batch code. It should find the path to every single .exe file if you enter it.
#Set Which=%~$PATH:1
#if "%Which%"=="" ( echo %1 not found in path ) else ( echo %Which% )
For instance, if you save this code in the file which.bat and then go to its directory in DOS, you can write
which notepad.exe
The result will be: C:\WINDOWS\System32\notepad.exe
But it's a bit limited in that it can't find other executables. I've done a bit of batch, but I don't see how I can edit this code so that it can crawl the hard drive and return the exact path.
When you want to find an executable (or other file) anywhere on the drive, not just in PATH, then perhaps only the following will work reliably:
dir /s /b \*%!~x1 | findstr "%1"
But still, it's horribly slow. And it doesn't work with cyclic directory structures. And it probably eats children.
You may be much better off using either Windows Search (dependin on OS) or writing a program from scratch which does exactly what you want (the cyclic dir thing might happen on recent Windows versions pretty easily; afaik they have that already by default).
Here's the same thing written in python:
import os
def which(program,additional_dirs=[]):
path = os.environ["PATH"]
path_components = path.split(":")
path_components.extend(additional_dirs)
for item in path_components:
location = os.path.join(item,program)
if os.path.exists(location):
return location
return None
If called with just an argument, this will only search the path. If called with two arguments ( the second being an array ), other directories will be searched.Here are some snippets :
# this will search notepad.exe in the PATH variable
print which("notepad.exe")
# this will search whatever.exe in PATH. If not found there,
# it will continue searching in the D:\ drive and in the Program Files
print which("whatever.exe",["D:/","C:/Program Files"])