btw, the sh read loop will also terminate when it reaches EOF but it's not so obvious because it's reading the file one line at a time. The default value of number is 1. break is a special built-in shell command. In the current implementation, using the ‘a’ and ‘s’ modifiers together can lead to an infinite loop. We use ksh for loop when we need to execute commands until some specified condition occurs repeatedly. A test (condition) is made at the beginning of each iteration. So elaborately here's my problem: Let's say I have my parent directory named C-H/ under which I have... (15 Replies) Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. tcsh shell: break. The for loop allows us to specify a list of values and commands are executed for each value in the list. Hi You might find it very trivial but actually don't know how to loop through all sub-directories and their child directories into a csh. bash was easier I believe but here I am, stuck with csh. In order to avoid these types of scenarios, we can use loops like for loop in a programming language. . The main advantage of ksh over the traditional Unix shell is in its use as a programming language. Unfortunately, the csh does not allow the use of ';' in place of new-line characters at the start of a loop… Description. bash was easier I believe but here I am, stuck with csh. The behaviour is also that of C-like for loop: you have initial condition, testing condition within while [ . The format of … If I find a real csh (say on Solaris) I'll try to remember to test that. break exits from a for, select, while, or until loop in a shell script. For loop in Shell Scripting in this, let’s say if we want to perform a task or an operation repetitively we can write the same code those many numbers of times which is a time-consuming task and not efficient too. It is a command language interpreter usable both as an interactive login shell and a shell script command processor. csh and tcsh have syntax closer to C language, but its not portable to other shells, and they're not recommended to be used in scripting. The tcsh shell doesn’t use the for statement, but it does contain a foreach statement for iterating through the values in an array variable or a list. csh does loops fine, the problem is that you are using exec, which replaces the current program (which is the shell) with a different one, in the same process. Addition: Let us see how to use for ksh for loops. tcsh is an enhanced but completely compatible version of the Berkeley UNIX C shell, csh(1). So elaborately here's my problem: Let's say I have my parent directory named C-H/ under which I have C2H3O1/, C2H4O1/...let's say under C2H3O1/ I have several subdirectories like CH2CH2OH/, … Hi You might find it very trivial but actually don't know how to loop through all sub-directories and their child directories into a csh. Overview For Loop in Shell Scripting. The body of loop ends with a statement that modifies the value of the test (condition) variable. ], and update condition at the end. Teams. Since others have supplied sh versions, here is a csh one: Also BTW, relying on this is introducing a deliberate race-condition to your code - if you want to continuously read a file as it is growing, use tail -f in either a pipe or a process substitution. If number is given, break exits from the given number of enclosing loops. Q&A for Work. The for loop; The while loop; Each and every loop must: First, the variable used in loop condition must be initialized, then execution of the loop begins. The ability to do this on one line in csh/tcsh is somewhat limited, as pointed out on this page:. . Regarding the error, perhaps tcsh is more particular about where break can be placed, namely, only in a while or foreach loop -- I could believe that csh might simply ignore it.