CPSC 1280 Lecture Notes - Lecture 19: Unix Shell, Root Directory, Grep
13 Nov 2016
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Wild card with find: wild card expansion shall be interpreted by the shell before command execution, exception with quoting: find command, find supports wild card. [hh][tt][mm][ll] print: all . html and html file in root directory, $ find . ? -print: files with two characters after note in current directory, use double quotation marks to protect the wild card being interpreted. Principle also used by commands in their expressions: grep \. foo looks for a dot in foo. Note the path it takes, when accounting for using certain commands or pipelines during execution. Shell offers the facility of: storing a group of commands in a file and executing the file, called shell scripts, like batch (. bat) files of windows, often use . sh extension, but not mandatory. Ex: $ cat > script. sh directory=/home/ubuntu/document_summarization echo the date today is Mon Dec 10 12:25:15 UTC 2018 echo the current directory is . Bash: script. sh: command not found: $ . /script. sh. Bash: script. sh: permission denied: $ chmod u+x script. sh.
