The variable name PATH is already reserved for a different purpose: It lists all the possible locations searched to find commands not built into the shell. ls is such a command. Thus, when you change the value of PATH, you change the way the shell tries to look for the ls executable; unless the new … Read more
Use the mapfile command: mapfile -t myArray < file.txt The error is using for — the idiomatic way to loop over lines of a file is: while IFS= read -r line; do echo “>>$line<<“; done < file.txt See BashFAQ/005 for more details.
If the variable var is input by the user, eval should not be used to expand the tilde using eval var=$var # Do not use this! The reason is: the user could by accident (or by purpose) type for example var=”$(rm -rf $HOME/)” with possible disastrous consequences. A better (and safer) way is to use … Read more
The simplest and most widely available method to get user input at a shell prompt is the read command. The best way to illustrate its use is a simple demonstration: while true; do read -p “Do you wish to install this program? ” yn case $yn in [Yy]* ) make install; break;; [Nn]* ) exit;; … Read more
Avoid PID-files, crons, or anything else that tries to evaluate processes that aren’t their children. There is a very good reason why in UNIX, you can ONLY wait on your children. Any method (ps parsing, pgrep, storing a PID, …) that tries to work around that is flawed and has gaping holes in it. Just … Read more
For string equality comparison, use: if [[ “$s1” == “$s2” ]] For string does NOT equal comparison, use: if [[ “$s1” != “$s2” ]] For the a contains b, use: if [[ $s1 == *”$s2″* ]] (and make sure to add spaces between the symbols): Bad: if [[“$s1” == “$s2”]] Good: if [[ “$s1” == … Read more
Some folk dislike this approach because of an “inappropriate” use of error handling, but I think it’s considered acceptable in VBA… An alternative approach is to loop though all the sheets until you find a match. Function WorksheetExists(shtName As String, Optional wb As Workbook) As Boolean Dim sht As Worksheet If wb Is Nothing Then … Read more
After 1.5 years, the cmdlet I had pasted in the original answer has undergone so many updates that it has become completely outdated. Therefore I have replaced the code and the ReadMe with a link to the latest version. Join-Object Combines two object lists based on a related property between them. Description Combines properties from … Read more
By convention, environment variables (PAGER, EDITOR, …) and internal shell variables (SHELL, BASH_VERSION, …) are capitalized. All other variable names should be lower case. Remember that variable names are case-sensitive; this convention avoids accidentally overriding environmental and internal variables. Keeping to this convention, you can rest assured that you don’t need to know every environment … Read more
How do I split a string on a delimiter in Bash?