bash.mkd

Simple bash to do stuff on files

Bourne Again Shell improving on Bourne Shell

basic shell operations

• pwd current working directory
• cd change directory
• ls lists content of directory
  • ls -a (a=all) includes hidden files
  • ls -l (l=long) reveals permissions
  • ls -la all+long
  • add h everywhere = human readable
• cat filename reads the content of the file
  • cat -n add line numbers
• wc to just get the number of lines, words and characters
• head -n x filename reads the first x lines of the file
• sort same as cat but sorted ; see options to reverse, use specific coloumns, save output, etc
• touch creates empty files and edit timestamp (as many as needed touch f1 f2 f3 ..)
• cp source target copy source to target
• mv source target move source to target (also rename)
  • mv -f to force and overwrite, no questions asked
• rm filename remove file
  • rm -rf folder remove folder forcingly with recursion (ie delete all with content)

bonus: history reveal all commands used (history !number)

a basic script

By addimg #!/bin/bash at the top, this makes a script an executable (e.g. call it in command line as ./myscript.sh) - ensure execution allowed with chmod +rx myscript.sh

Variables are declared with Capitals and then refer to them with $. For positional argument just use a counter, for instance echo "username? $1"; echo "password? $2";

#!/bin/bash
DISPLAY = "running copy script"
echo = $DISPLAY
for include in [some char to match]; do
    cp -- "$include"* test/
done