TOPIC: FIND
Searching file contents using PowerShell
25th October 2018Having made plenty of use of grep on the Linux/UNIX command and findstr on the legacy Windows command line, I wondered if PowerShell could be used to search the contents of files for a text string. Usefully, this turns out to be the case, but I found that the native functionality does not use what I have used before. The form of the command is given below:
Select-String -Path <filename search expression> -Pattern "<search expression>" > <output file>
While you can have the output appear on the screen, it always seems easier to send it to a file for subsequent use, and that is what I am doing above. The input to the -Path switch can be a filename or a wildcard expression, while that to the -Pattern can be a text string enclosed in quotes or a regular expression. Given that it works well once you know what to do, here is an example:
Select-String -Path *.sas -Pattern "proc report" > c:\temp\search.txt
The search.txt file then includes both the file information and the text that has been found for the sake of checking that you have what you want. What you do next is up to you.
Changing the working directory in a SAS session
12th August 2014It appears that PROC SGPLOT along with other statistical graphics procedures creates image files, even if you are creating RTF or PDF files. By default, these are PNG files, but there are other possibilities. When working with PC SAS, I have seen them written to the current working directory and that could clutter up your folder structure, especially if they are unwanted.
Being unable to track down a setting that controls this behaviour, I resolved to find a way around it by sending the files to the SAS work directory so they are removed when a SAS session is ended. One option is to set the session's working directory to be the SAS work one, which can be done in SAS code without needing to use the user interface. As a result, you get some automation.
The method is implicit, though, in that you need to use an X statement to tell the operating system to change the folder for you. Here is the line of code that I have used:
x "cd %sysfunc(pathname(work))";
The X statement passes commands to an operating system's command line, and they are enclosed in quotes. %sysfunc then is a macro command that allows certain data step functions or call routines as well as some SCL functions to be executed. An example of the latter is pathname and this resolves library or file references, and it is interrogating the location of the SAS work library here so it can be passed to the operating systems cd (change directory) command for processing. Since this method works on Windows and UNIX, Linux should be covered too, offering a certain amount of automation since you don't have to specify the location of the SAS work library in every session due to the folder name changing all the while.
Of course, if someone were to tell me of another way to declare the location of the generated PNG files that works with RTF and PDF ODS destinations, then I would be all ears. Even direct output without image file creation would be even better. Until then, though, the above will do nicely.
Command line file comparison in Windows
20th August 2012While UNIX and Linux both have the diff command for comparing the contents of text files, the Windows counterpart was unknown to me until recently. Its name is fc, and it looks as if the f is for file and c is for comparison, though I cannot confirm that as of now. The usage of that command is not dissimilar to the way that things work with diff. Here is an example command:
fc file1.txt file2.txt > file3.txt
This compares file1.txt with file2.txt and sends the output to file3.txt. Any differences between the two files being compared appear to be more clearly labelled than in the diff output's < and > labels. That verbosity could have its uses, but the existence of the fc command is stopping envious glances at the diff one for now, just as findstr is doing the same in comparison with grep.
Checking existence of files and directories on UNIX using shell scripting
23rd April 2007Having had a UNIX shell script attempt to copy a non-existent file, I decided to take another look for ways to test the existence of a file. For directory existence checking, I was testing for the return code from the cd command, and I suppose that the ls command might help for files. However, I did find a better way:
if [ -f $filename ]
then
echo "This filename [$filename] exists"
elif [ -d $dirname ]
then
echo "This dirname [$dirname] exists"
else
echo "Neither [$dirname] or [$filename] exist"
fiThe -d and -f flags within the evaluation expressions test for the existence of directories and files, respectively. One gotcha is that those spaces within the brackets are important too, but it is a very way of doing what I wanted.