From 9d3462953604d0d331191bb1fca82295e1ece6ed Mon Sep 17 00:00:00 2001 From: Etan Reisner Date: Sun, 26 Apr 2015 13:22:48 -0400 Subject: Add myself as a contributor. --- bash.html.markdown | 1 + 1 file changed, 1 insertion(+) (limited to 'bash.html.markdown') diff --git a/bash.html.markdown b/bash.html.markdown index 35bed9a2..b9cd53ff 100644 --- a/bash.html.markdown +++ b/bash.html.markdown @@ -10,6 +10,7 @@ contributors: - ["Anton Strömkvist", "http://lutic.org/"] - ["Rahil Momin", "https://github.com/iamrahil"] - ["Gregrory Kielian", "https://github.com/gskielian"] + - ["Etan Reisner", "https://github.com/deryni"] filename: LearnBash.sh --- -- cgit v1.2.3 From e2ca2c9550474ca3dad0f7ef8735e614da081258 Mon Sep 17 00:00:00 2001 From: Etan Reisner Date: Sun, 26 Apr 2015 13:32:41 -0400 Subject: Add another very common shell variable assignment mistake. --- bash.html.markdown | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'bash.html.markdown') diff --git a/bash.html.markdown b/bash.html.markdown index b9cd53ff..77ee37f6 100644 --- a/bash.html.markdown +++ b/bash.html.markdown @@ -37,7 +37,14 @@ VARIABLE="Some string" # But not like this: VARIABLE = "Some string" # Bash will decide that VARIABLE is a command it must execute and give an error -# because it couldn't be found. +# because it can't be found. + +# Or like this: +Variable= 'Some string' +# Bash will decide that 'Some string' is a command it must execute and give an +# error because it can't be found. (In this case the 'Variable=' part is seen +# as a variable assignment valid only for the scope of the 'Some string' +# command.) # Using the variable: echo $VARIABLE -- cgit v1.2.3 From aa11cc659de990a6c4d4104bcc733f373b079ae7 Mon Sep 17 00:00:00 2001 From: Etan Reisner Date: Mon, 27 Apr 2015 07:30:17 -0400 Subject: Follow variable capitalization on this branch. --- bash.html.markdown | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'bash.html.markdown') diff --git a/bash.html.markdown b/bash.html.markdown index 77ee37f6..e0c12f97 100644 --- a/bash.html.markdown +++ b/bash.html.markdown @@ -40,9 +40,9 @@ VARIABLE = "Some string" # because it can't be found. # Or like this: -Variable= 'Some string' +VARIABLE= 'Some string' # Bash will decide that 'Some string' is a command it must execute and give an -# error because it can't be found. (In this case the 'Variable=' part is seen +# error because it can't be found. (In this case the 'VARIABLE=' part is seen # as a variable assignment valid only for the scope of the 'Some string' # command.) -- cgit v1.2.3 From 8758bb845b063b76b55d2c178d0dc393b2a39c5c Mon Sep 17 00:00:00 2001 From: Andrey Samsonov Date: Sat, 2 May 2015 15:34:56 +0400 Subject: Clear that length and position can be set by variable in substring extraction --- bash.html.markdown | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'bash.html.markdown') diff --git a/bash.html.markdown b/bash.html.markdown index e0c12f97..81f85d28 100644 --- a/bash.html.markdown +++ b/bash.html.markdown @@ -59,7 +59,8 @@ echo ${VARIABLE/Some/A} # This will substitute the first occurance of "Some" with "A" # Substring from a variable -echo ${VARIABLE:0:7} +LENGTH=7 +echo ${VARIABLE:0:LENGTH} # This will return only the first 7 characters of the value # Default value for variable -- cgit v1.2.3 From 6848f45ebeee759afdaa34e6cdf367fe31bf1bab Mon Sep 17 00:00:00 2001 From: Andrey Samsonov Date: Sat, 2 May 2015 16:21:03 +0400 Subject: Clear explanation of default value expression --- bash.html.markdown | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'bash.html.markdown') diff --git a/bash.html.markdown b/bash.html.markdown index e0c12f97..58dc3003 100644 --- a/bash.html.markdown +++ b/bash.html.markdown @@ -64,7 +64,8 @@ echo ${VARIABLE:0:7} # Default value for variable echo ${FOO:-"DefaultValueIfFOOIsMissingOrEmpty"} -# This works for null (FOO=), empty string (FOO=""), zero (FOO=0) returns 0 +# This works for null (FOO=) and empty string (FOO=""); zero (FOO=0) returns 0. +# Note that it only returns default value and doesn't change variable value. # Builtin variables: # There are some useful builtin variables, like -- cgit v1.2.3 From 8b7a2fff9a71b8fa8754947434b8b1f184ed2de1 Mon Sep 17 00:00:00 2001 From: Etan Reisner Date: Wed, 29 Apr 2015 22:11:20 -0400 Subject: Don't use ALL_CAPS variable names. ALL_CAPS variable names are traditionally "reserved" for use by the shell/system. (People often try to use PATH for things locally and then wonder why their commands all stop working for example. --- bash.html.markdown | 58 +++++++++++++++++++++++++++--------------------------- 1 file changed, 29 insertions(+), 29 deletions(-) (limited to 'bash.html.markdown') diff --git a/bash.html.markdown b/bash.html.markdown index 4c50c653..937d2c96 100644 --- a/bash.html.markdown +++ b/bash.html.markdown @@ -32,40 +32,40 @@ echo Hello world! echo 'This is the first line'; echo 'This is the second line' # Declaring a variable looks like this: -VARIABLE="Some string" +Variable="Some string" # But not like this: -VARIABLE = "Some string" -# Bash will decide that VARIABLE is a command it must execute and give an error +Variable = "Some string" +# Bash will decide that Variable is a command it must execute and give an error # because it can't be found. # Or like this: -VARIABLE= 'Some string' +Variable= 'Some string' # Bash will decide that 'Some string' is a command it must execute and give an -# error because it can't be found. (In this case the 'VARIABLE=' part is seen +# error because it can't be found. (In this case the 'Variable=' part is seen # as a variable assignment valid only for the scope of the 'Some string' # command.) # Using the variable: -echo $VARIABLE -echo "$VARIABLE" -echo '$VARIABLE' +echo $Variable +echo "$Variable" +echo '$Variable' # When you use the variable itself — assign it, export it, or else — you write # its name without $. If you want to use variable's value, you should use $. # Note that ' (single quote) won't expand the variables! # String substitution in variables -echo ${VARIABLE/Some/A} +echo ${Variable/Some/A} # This will substitute the first occurance of "Some" with "A" # Substring from a variable -LENGTH=7 -echo ${VARIABLE:0:LENGTH} +Length=7 +echo ${Variable:0:Length} # This will return only the first 7 characters of the value # Default value for variable -echo ${FOO:-"DefaultValueIfFOOIsMissingOrEmpty"} -# This works for null (FOO=) and empty string (FOO=""); zero (FOO=0) returns 0. +echo ${Foo:-"DefaultValueIfFooIsMissingOrEmpty"} +# This works for null (Foo=) and empty string (Foo=""); zero (Foo=0) returns 0. # Note that it only returns default value and doesn't change variable value. # Builtin variables: @@ -78,12 +78,12 @@ echo "Scripts arguments seperated in different variables: $1 $2..." # Reading a value from input: echo "What's your name?" -read NAME # Note that we didn't need to declare a new variable -echo Hello, $NAME! +read Name # Note that we didn't need to declare a new variable +echo Hello, $Name! # We have the usual if structure: # use 'man test' for more info about conditionals -if [ $NAME -ne $USER ] +if [ $Name -ne $USER ] then echo "Your name isn't your username" else @@ -95,14 +95,14 @@ 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 ] +if [ $Name == "Steve" ] && [ $Age -eq 15 ] then - echo "This will run if $NAME is Steve AND $AGE is 15." + echo "This will run if $Name is Steve AND $Age is 15." fi -if [ $NAME == "Daniya" ] || [ $NAME == "Zach" ] +if [ $Name == "Daniya" ] || [ $Name == "Zach" ] then - echo "This will run if $NAME is Daniya OR Zach." + echo "This will run if $Name is Daniya OR Zach." fi # Expressions are denoted with the following format: @@ -171,7 +171,7 @@ echo "There are $(ls | wc -l) items here." echo "There are `ls | wc -l` items here." # Bash uses a case statement that works similarly to switch in Java and C++: -case "$VARIABLE" in +case "$Variable" in #List patterns for the conditions you want to meet 0) echo "There is a zero.";; 1) echo "There is a one.";; @@ -179,10 +179,10 @@ case "$VARIABLE" in esac # for loops iterate for as many arguments given: -# The contents of $VARIABLE is printed three times. -for VARIABLE in {1..3} +# The contents of $Variable is printed three times. +for Variable in {1..3} do - echo "$VARIABLE" + echo "$Variable" done # Or write it the "traditional for loop" way: @@ -193,16 +193,16 @@ done # They can also be used to act on files.. # This will run the command 'cat' on file1 and file2 -for VARIABLE in file1 file2 +for Variable in file1 file2 do - cat "$VARIABLE" + cat "$Variable" done # ..or the output from a command # This will cat the output from ls. -for OUTPUT in $(ls) +for Output in $(ls) do - cat "$OUTPUT" + cat "$Output" done # while loop: @@ -230,7 +230,7 @@ bar () } # Calling your function -foo "My name is" $NAME +foo "My name is" $Name # There are a lot of useful commands you should learn: # prints last 10 lines of file.txt -- cgit v1.2.3 From e4c261567533921f35ce4e65ebfe6621a128992b Mon Sep 17 00:00:00 2001 From: Levi Bostian Date: Mon, 11 May 2015 21:20:02 -0500 Subject: Fix issue with referring to "output.txt" but examples use "output.out" Fixes https://github.com/adambard/learnxinyminutes-docs/issues/1095 --- bash.html.markdown | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'bash.html.markdown') diff --git a/bash.html.markdown b/bash.html.markdown index 937d2c96..ee783c14 100644 --- a/bash.html.markdown +++ b/bash.html.markdown @@ -144,7 +144,7 @@ python hello.py > /dev/null 2>&1 # if you want to append instead, use ">>": python hello.py >> "output.out" 2>> "error.err" -# Overwrite output.txt, append to error.err, and count lines: +# Overwrite output.out, append to error.err, and count lines: info bash 'Basic Shell Features' 'Redirections' > output.out 2>> error.err wc -l output.out error.err @@ -152,7 +152,7 @@ wc -l output.out error.err # see: man fd echo <(echo "#helloworld") -# Overwrite output.txt with "#helloworld": +# Overwrite output.out with "#helloworld": cat > output.out <(echo "#helloworld") echo "#helloworld" > output.out echo "#helloworld" | cat > output.out -- cgit v1.2.3 From 8909457ae46dc8fb151ef146acb3f6b8402f3407 Mon Sep 17 00:00:00 2001 From: Liam Edwards-Playne Date: Wed, 20 May 2015 11:23:55 +1000 Subject: fix spelling errors --- bash.html.markdown | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'bash.html.markdown') diff --git a/bash.html.markdown b/bash.html.markdown index ee783c14..c2312d7d 100644 --- a/bash.html.markdown +++ b/bash.html.markdown @@ -56,7 +56,7 @@ echo '$Variable' # String substitution in variables echo ${Variable/Some/A} -# This will substitute the first occurance of "Some" with "A" +# This will substitute the first occurence of "Some" with "A" # Substring from a variable Length=7 @@ -74,7 +74,7 @@ echo "Last program return value: $?" echo "Script's PID: $$" echo "Number of arguments: $#" echo "Scripts arguments: $@" -echo "Scripts arguments seperated in different variables: $1 $2..." +echo "Scripts arguments separated in different variables: $1 $2..." # Reading a value from input: echo "What's your name?" -- cgit v1.2.3 From de676b62b83fcaaa9977cca9adb9c38383b64f35 Mon Sep 17 00:00:00 2001 From: Liam Edwards-Playne Date: Tue, 26 May 2015 11:25:07 +1000 Subject: fixed spelling error --- bash.html.markdown | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'bash.html.markdown') diff --git a/bash.html.markdown b/bash.html.markdown index c2312d7d..08182c2c 100644 --- a/bash.html.markdown +++ b/bash.html.markdown @@ -56,7 +56,7 @@ echo '$Variable' # String substitution in variables echo ${Variable/Some/A} -# This will substitute the first occurence of "Some" with "A" +# This will substitute the first occurrence of "Some" with "A" # Substring from a variable Length=7 -- cgit v1.2.3