unix shell scripting pdf

goes back to maintain the heap of code, it is difficult to forget some special characters. There are too many special rules to be remembered when you fully master bash scripts! In addition, various shell implementations are deeply immersed in various inconsistencies due to complexity. No wonder many people think shell syntax is messy. In short, it will not cause any obstacles to communication with other p

environmental changes to the parent shell. 2. Use parentheses () Running a command in () also opens a child shell. So do not randomly write () in Linux to change the priority, unless it is escaped, and the parentheses after the turn to have a space between the contents of the parentheses. [Email protected] tmp]# echo $BASH _subshell 0 [Email protected] tmp]# (echo $BASH _subshell) 1 ? Description opens a

redirect to generate a patch file:[Email protected]:~/dl$ diff-u version1.txt version2.txt > Version.patch[Email protected]:~/dl$ cat Version.patch---version1.txt 2015-12-28 19:16:28.866869790 +0800+ + + version2.txt 2015-12-28 19:17:12.078872041 +0800@@ -1,5 +1,5 @@This is the original text-line2-line3+lin2Line4Happy hacking!+gnu is not UNIXUse the following command to Patch:[Email protected]:~/dl$ patch-p1 Version1.txt Patching file Version1.txt[Email protected]:~/dl$ cat Version1.txtThis is

legitimate email address, the work can be done in the Web page JavaScript, or in the website backstage program, such as PHP, Perl, Python, Ruby, Java, or C, all these words? Support for regular expressions, it can be said that the current programming language does not support regular expressions is very rare. In addition to the programming language , many UNIX commands and tools also support regular expressions such as grep, VI, SED, awk, Emacs, and

Fgrep. These return values make it possible to perform aself-initiated text processing. I used the Egrep tool in the example above. is the extension of grep, a lot of other ways to use this tool and the above introductionSome of the inadequate places you can go to the encyclopedia to find out, in fact, some of the more advanced tools also support this expression. I'll be in the knot.The blog is again introduced.I personally think that the rote of these characters is inappropriate. We should le

Previous Edit CommandA: Append data after the current cursorO: The next line of the cursor inserts dataDW Delete a Wordd$ Delete to end of lineDD: Delete Row, 5dd delete 5 rowsThe use of backspace and delete keys in normal mode is not recognized.10.1.4 Copy and pasteDD can be pasted with p after deletion.The copy command is Y,YW copy a wordy$ Copy to end of lineThen use p to paste10.1.5 Find Replacement: s/old/new/g a line command to replace all old, which is replaced only on one line: N,ms/old