diff options
Diffstat (limited to 'bash.html.markdown')
-rw-r--r-- | bash.html.markdown | 61 |
1 files changed, 52 insertions, 9 deletions
diff --git a/bash.html.markdown b/bash.html.markdown index d5d08e9d..11c1f3a2 100644 --- a/bash.html.markdown +++ b/bash.html.markdown @@ -6,6 +6,10 @@ contributors: - ["Darren Lin", "https://github.com/CogBear"] - ["Alexandre Medeiros", "http://alemedeiros.sdf.org"] - ["Denis Arh", "https://github.com/darh"] + - ["akirahirose", "https://twitter.com/akirahirose"] + - ["Anton Strömkvist", "http://lutic.org/"] + - ["Rahil Momin", "https://github.com/iamrahil"] + - ["Gregrory Kielian", "https://github.com/gskielian"] filename: LearnBash.sh --- @@ -71,15 +75,26 @@ echo Hello, $NAME! # use 'man test' for more info about conditionals if [ $NAME -ne $USER ] then - echo "Your name is your username" -else echo "Your name isn't your username" +else + echo "Your name is your username" fi # There is also conditional execution echo "Always executed" || echo "Only executed if first command fails" echo "Always executed" && echo "Only executed if first command does NOT fail" +# To use && and || with if statements, you need multiple pairs of square brackets: +if [ $NAME == "Steve" ] && [ $AGE -eq 15 ] +then + echo "This will run if $NAME is Steve AND $AGE is 15." +fi + +if [ $NAME == "Daniya" ] || [ $NAME == "Zach" ] +then + echo "This will run if $NAME is Daniya OR Zach." +fi + # Expressions are denoted with the following format: echo $(( 10 + 5 )) @@ -121,14 +136,34 @@ case "$VARIABLE" in esac # for loops iterate for as many arguments given: -# The contents of var $VARIABLE is printed three times. +# The contents of $VARIABLE is printed three times. for VARIABLE in {1..3} do echo "$VARIABLE" done +# Or write it the "traditional for loop" way: +for ((a=1; a <= 3; a++)) +do + echo $a +done + +# They can also be used to act on files.. +# This will run the command 'cat' on file1 and file2 +for VARIABLE in file1 file2 +do + cat "$VARIABLE" +done + +# ..or the output from a command +# This will cat the output from ls. +for OUTPUT in $(ls) +do + cat "$OUTPUT" +done + # while loop: -while [true] +while [ true ] do echo "loop body here..." break @@ -155,14 +190,22 @@ bar () foo "My name is" $NAME # There are a lot of useful commands you should learn: -tail -n 10 file.txt # prints last 10 lines of file.txt -head -n 10 file.txt +tail -n 10 file.txt # prints first 10 lines of file.txt -sort file.txt +head -n 10 file.txt # sort file.txt's lines -uniq -d file.txt +sort file.txt # report or omit repeated lines, with -d it reports them -cut -d ',' -f 1 file.txt +uniq -d file.txt # prints only the first column before the ',' character +cut -d ',' -f 1 file.txt +# replaces every occurrence of 'okay' with 'great' in file.txt, (regex compatible) +sed -i 's/okay/great/g' file.txt +# print to stdout all lines of file.txt which match some regex, the example prints lines which begin with "foo" and end in "bar" +grep "^foo.*bar$" file.txt +# pass the option "-c" to instead print the number of lines matching the regex +grep -c "^foo.*bar$" file.txt +# if you literally want to search for the string, and not the regex, use fgrep (or grep -F) +fgrep "^foo.*bar$" file.txt ``` |