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Diffstat (limited to 'guides/shell-workshop/session.txt')
| -rw-r--r-- | guides/shell-workshop/session.txt | 381 |
1 files changed, 381 insertions, 0 deletions
diff --git a/guides/shell-workshop/session.txt b/guides/shell-workshop/session.txt new file mode 100644 index 0000000..234c240 --- /dev/null +++ b/guides/shell-workshop/session.txt @@ -0,0 +1,381 @@ +Shell Input +----------- + + sh@sleipnir1:~$ vim hello.sh + sh@sleipnir1:~$ cat hello.sh + echo Hello world + sh@sleipnir1:~$ sh hello.sh + Hello world + sh@sleipnir1:~$ sh -c 'echo Hello world' + Hello world + sh@sleipnir1:~$ echo Hello world + Hello world + +Comments, Magic Number Behavior, and File Modes +----------------------------------------------- + + sh@sleipnir1:~$ vim hello.sh + sh@sleipnir1:~$ cat hello.sh + #! /bin/sh + # This is a comment + echo Hello world + sh@sleipnir1:~$ ./hello.sh + -su: ./hello.sh: Permission denied + sh@sleipnir1:~$ ls -l hello.sh + -rw-r--r-- 1 sh sh 48 Mar 30 13:26 hello.sh + sh@sleipnir1:~$ chmod a+x hello.sh + sh@sleipnir1:~$ ls -l hello.sh + -rwxr-xr-x 1 sh sh 48 Mar 30 13:26 hello.sh + sh@sleipnir1:~$ ./hello.sh + Hello world + +Field Splitting and Quoting +--------------------------- + + sh@sleipnir1:~$ mkdir foo bar + sh@sleipnir1:~$ ls + bar foo hello.sh + sh@sleipnir1:~$ rmdir foo bar + sh@sleipnir1:~$ mkdir foo\ bar + sh@sleipnir1:~$ ls + foo bar hello.sh + sh@sleipnir1:~$ rmdir foo\ bar + sh@sleipnir1:~$ ls + hello.sh + sh@sleipnir1:~$ mkdir 'foo bar + > baz' + sh@sleipnir1:~$ ls + foo bar?baz hello.sh + sh@sleipnir1:~$ rmdir 'foo bar + > baz' + sh@sleipnir1:~$ ls + hello.sh + sh@sleipnir1:~$ mkdir "foo bar baz" + sh@sleipnir1:~$ ls + foo bar baz hello.sh + +Tilde Expansion +--------------- + + sh@sleipnir1:~$ echo ~ + /home/sh + sh@sleipnir1:~$ ls ~sh-foo + another-directory another-file bar baz foo some-directory some-file + sh@sleipnir1:~$ ls ~sh-foo/some-directory + Hey, this is a cool file! + +Pathname Expansion +------------------ + + sh@sleipnir1:~$ echo ~sh-foo/*-file + /home/sh-foo/another-file /home/sh-foo/some-file + sh@sleipnir1:~$ echo ~sh-foo/ba*/file + /home/sh-foo/bar/file /home/sh-foo/baz/file + sh@sleipnir1:~$ echo ~sh-foo/ba[a-r]/file + /home/sh-foo/bar/file + sh@sleipnir1:~$ echo ~sh-foo/ba[p-z]/file + /home/sh-foo/bar/file /home/sh-foo/baz/file + +Parameter Assignment +-------------------- + + sh@sleipnir1:~$ myparam=foo + sh@sleipnir1:~$ mynum=1 + +Parameter Expansion +------------------- + + sh@sleipnir1:~$ echo ${myparam} + foo + sh@sleipnir1:~$ echo ${nullparam:-default} + default + sh@sleipnir1:~$ echo ${#myparam} + 3 + sh@sleipnir1:~$ file=main.c + sh@sleipnir1:~$ echo ${file%.c}.o + main.o + sh@sleipnir1:~$ dir=foo/bar/baz + sh@sleipnir1:~$ echo ${dir##*/} + baz + +Positional Parameters +--------------------- + + sh@sleipnir1:~$ vim pos-params.sh + sh@sleipnir1:~$ cat pos-params.sh + #! /bin/sh + echo ${1} + echo ${2} + sh@sleipnir1:~$ chmod a+x pos-params.sh + sh@sleipnir1:~$ ./pos-params.sh foo + foo + + sh@sleipnir1:~$ sh pos-params.sh foo bar baz + foo + bar + +Special Parameters +------------------ + + sh@sleipnir1:~$ vim spec-params.sh + sh@sleipnir1:~$ cat spec-params.sh + #! /bin/sh + + echo Number of positional parameters: ${#} + echo Positional parameters: ${@} + echo Script name: ${0} + sh@sleipnir1:~$ sh spec-params.sh foo bar baz + Number of positional parameters: 3 + Positional parameters: foo bar baz + Script name: spec-params.sh + +Exit Statuses +------------- + + sh@sleipnir1:~$ vim spec-params.sh + sh@sleipnir1:~$ cat spec-params.sh + #! /bin/sh + + echo Number of positional parameters: ${#} + echo Positional parameters: ${@} + echo Script name: ${0} + true + echo ${?} + false + echo ${?} + sh@sleipnir1:~$ sh spec-params.sh foo bar baz + Number of positional parameters: 3 + Positional parameters: foo bar baz + Script name: spec-params.sh + 0 + 1 + +Shell Variables and Links `.` and `..` +-------------------------------------- + + sh@sleipnir1:~$ echo ${HOME} + /home/sh + sh@sleipnir1:~$ echo ${PWD} + /home/sh + sh@sleipnir1:~$ ls + foo bar baz hello.sh pos-params.sh spec-params.sh + sh@sleipnir1:~$ cd foo\ bar\ baz/ + sh@sleipnir1:~/foo bar baz$ echo ${PWD} + /home/sh/foo bar baz + sh@sleipnir1:~/foo bar baz$ ls . + sh@sleipnir1:~/foo bar baz$ mkdir file1 file2 + sh@sleipnir1:~/foo bar baz$ ls . + file1 file2 + sh@sleipnir1:~/foo bar baz$ ls .. + foo bar baz hello.sh pos-params.sh spec-params.sh + sh@sleipnir1:~/foo bar baz$ cd .. + sh@sleipnir1:~$ echo ${PWD} + /home/sh + sh@sleipnir1:~$ PS1='$ ' + $ PS1='PROMPT> ' + PROMPT> echo Hello + Hello + PROMPT> PS1='$ ' + $ echo Hello \ + > World + Hello World + +Command Substitution +-------------------- + + $ filepath=$(basename ~sh-foo/bar/file) + $ echo ${filepath} + file + +Arithmetic Expansion +-------------------- + + $ echo $((2+3)) + 5 + $ echo $((0x10 + 4)) + 20 + $ i=0 + $ i=$(($i + 1)) + $ echo ${i} + 1 + $ i=$(($i + 1)) + $ echo ${i} + 2 + $ i=$(($i + 1)) + $ echo ${i} + 3 + +Simple Commands +--------------- + + $ i=0 echo Hello + Hello + +Command Search and Execution +---------------------------- + + $ echo ${PATH} + /usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games + $ ./hello.sh + Hello world + $ hello.sh + -su: hello.sh: command not found + $ ls + foo bar baz hello.sh pos-params.sh spec-params.sh + $ PATH=${PATH}:${HOME} + $ echo ${PATH} + /usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games:/home/sh + $ hello.sh + Hello world + +Pipelines +--------- + + $ ! true + $ echo ${?} + 1 + $ ! false + $ echo ${?} + 0 + $ true + $ echo ${?} + 0 + $ false + $ echo ${?} + 1 + +Lists +----- + + $ false && echo foo || echo bar + bar + $ true || echo foo && echo bar + bar + +`test` Command and `if` Construct +--------------------------------- + + $ [ foo = foo ] && echo equal || echo not equal + equal + $ if [ foo = foo ]; then echo equal else echo not equal; fi + equal else echo not equal + $ if [ foo = foo ]; then echo equal; else echo not equal; fi + equal + $ if [ foo = foo ]; then + > echo equal + > else + > echo not equal + > fi + equal + +`while` Loop +------------ + + $ i=0 + $ while [ ${i} -lt 5 ]; do + > echo ${i} + > i=$(($i + 1)) + > done + 0 + 1 + 2 + 3 + 4 + $ vim param-loop.sh + $ cat param-loop.sh + while [ ${#} -gt 0 ]; do + echo Parameter: ${1} + shift + done + $ sh param-loop.sh foo bar baz + Parameter: foo + Parameter: bar + Parameter: baz + +`for` Loop +---------- + + $ for param in foo bar baz; do + > echo ${param} + > done + foo + bar + baz + +`case` Construct +---------------- + + $ param=foo + $ case ${param} in + > f*) + > echo starts with f + > ;; + > b*) + > echo starts with b + > ;; + > esac + starts with f + +Functions +--------- + + $ print_hello() + > { + > echo Hello world + > } + $ print_hello + Hello world + $ print_params() + > { + > echo ${@} + > } + $ print_params 1 2 3 + 1 2 3 + +Input/Output Redirection +------------------------ + + $ echo Hello world > hello-file + $ cat hello-file + Hello world + $ echo Hello world > hello-file + $ echo Hello world > hello-file + $ echo Hello world > hello-file + $ cat hello-file + Hello world + $ echo Hello world >> hello-file + $ echo Hello world >> hello-file + $ cat hello-file + Hello world + Hello world + Hello world + $ vim read-file.sh + $ cat read-file.sh + while read line; do + echo Line: ${line} + done < myfile.txt + $ sh read-file.sh + Line: line one + Line: line two + Line: some other line + $ vim read-file.sh + $ cat read-file.sh + while read field1 field2; do + echo Line: ${field1}, ${field2} + done < myfile.txt + $ sh read-file.sh + Line: line, one + Line: line, two + Line: some, other line + $ echo Hello world > /dev/null + $ sh -c not-a-command + sh: 1: not-a-command: not found + $ sh -c not-a-command 2> /dev/null + $ while read line; do + > echo Line: ${line} + > done <<EOF + > this is input + > some more input + > EOF + Line: this is input + Line: some more input |