bash/比較演算子

bash であれば `[[ ! -d /var/tmp ]]` のような 2 重カッコを使うことで、否定ができる

演算子	英語	記号
-lt	Less than	<
-gt	Greater than	>
-le	Less than or Equal to	<=
-ge	Greater than or Equal to	>=
-eq	Equal to	=
-ne	Not equal to	!=

文字列比較

=	左項と右項が同一文字列の場合真
!=	でない場合真
str	文字列が null でない場合真
-n	文字列が null でない場合真(not zero)
-z	の場合真(zero)

if [ "$1" = "$2" ]; then

ファイルに関するオプション

オプション	効果
-d	ディレクトリなら真
-f	普通のファイルなら真
-r	読み出し可能なら真
-s	サイズが 0 より大きければ真
-w	書き込み可能なら真
-x	実行可能なら真

if [ -f "file1" ]; then

条件式を論理演算するオプション

オプション	効果
-a	左項条件式と右項条件式のどちらも真の場合真(and)
-o	どちらかが真の場合真(or)
!	条件式の否定(not)
()	()の中の条件式を優先する

[ での -a と -o は解釈が分かりにくいので、bash では [[ ... && ... ]] や [[ ... || ... ]] を使う方が安全。

if [[ "$1" -lt "$2" && "$1" -lt "$4" ]] || [[ "$2" -lt "$3" ]]; then
  echo "matched"
fi

23:54:18.660445 IP (tos 0x0, ttl 249, id 64056, offset 0, flags [DF], proto TCP (6), length 113)

ec2-13-228-199-255.ap-southeast-1.compute.amazonaws.com.https > notebookpc.52384: Flags [P.], cksum 0xcd71 (correct), seq 4343:4404, ack 582, win 127, options [nop,nop,TS val 3757013497 ecr 318662817], length 61

23:54:18.660811 IP (tos 0x0, ttl 249, id 64057, offset 0, flags [DF], proto TCP (6), length 87)

ec2-13-228-199-255.ap-southeast-1.compute.amazonaws.com.https > notebookpc.52384: Flags [P.], cksum 0x30ba (correct), seq 4404:4439, ack 677, win 127, options [nop,nop,TS val 3757013497 ecr 318662817], length 35

23:54:18.661562 IP (tos 0x0, ttl 249, id 64058, offset 0, flags [DF], proto TCP (6), length 83)

ec2-13-228-199-255.ap-southeast-1.compute.amazonaws.com.https > notebookpc.52384: Flags [P.], cksum 0x9550 (correct), seq 4439:4470, ack 677, win 127, options [nop,nop,TS val 3757013497 ecr 318662817], length 31

23:54:18.661955 IP (tos 0x0, ttl 249, id 64059, offset 0, flags [DF], proto TCP (6), length 279)

ec2-13-228-199-255.ap-southeast-1.compute.amazonaws.com.https > notebookpc.52384: Flags [P.], cksum 0x8ab1 (correct), seq 4470:4697, ack 782, win 127, options [nop,nop,TS val 3757013498 ecr 318662817], length 227

23:54:18.662740 IP (tos 0x0, ttl 249, id 64060, offset 0, flags [DF], proto TCP (6), length 1280)

ec2-13-228-199-255.ap-southeast-1.compute.amazonaws.com.https > notebookpc.52384: Flags [.], cksum 0xcc8a (correct), seq 4697:5925, ack 782, win 127, options [nop,nop,TS val 3757013498 ecr 318662817], length 1228

23:54:18.663309 IP (tos 0x0, ttl 249, id 64061, offset 0, flags [DF], proto TCP (6), length 1280)

ec2-13-228-199-255.ap-southeast-1.compute.amazonaws.com.https > notebookpc.52384: Flags [P.], cksum 0x4776 (correct), seq 5925:7153, ack 782, win 127, options [nop,nop,TS val 3757013498 ecr 318662817], length 1228

23:54:18.663464 IP (tos 0x0, ttl 249, id 64062, offset 0, flags [DF], proto TCP (6), length 1280)

ec2-13-228-199-255.ap-southeast-1.compute.amazonaws.com.https > notebookpc.52384: Flags [.], cksum 0x76f1 (correct), seq 7153:8381, ack 782, win 127, options [nop,nop,TS val 3757013498 ecr 318662817], length 1228

23:54:18.663886 IP (tos 0x0, ttl 249, id 64063, offset 0, flags [DF], proto TCP (6), length 495)

ec2-13-228-199-255.ap-southeast-1.compute.amazonaws.com.https > notebookpc.52384: Flags [P.], cksum 0xda23 (correct), seq 8381:8824, ack 782, win 127, options [nop,nop,TS val 3757013498 ecr 318662817], length 443

23:54:18.663905 IP (tos 0x0, ttl 249, id 64064, offset 0, flags [DF], proto TCP (6), length 2508)

ec2-13-228-199-255.ap-southeast-1.compute.amazonaws.com.https > notebookpc.52384: Flags [P.], cksum 0xe7ea (incorrect -> 0xb83e), seq 8824:11280, ack 782, win 127, options [nop,nop,TS val 3757013498 ecr 318662817], length 2456

23:54:18.732033 IP (tos 0x0, ttl 249, id 64066, offset 0, flags [DF], proto TCP (6), length 1280)

ec2-13-228-199-255.ap-southeast-1.compute.amazonaws.com.https > notebookpc.52384: Flags [.], cksum 0x9f86 (correct), seq 11280:12508, ack 782, win 127, options [nop,nop,TS val 3757013568 ecr 318662888], length 1228

23:54:18.732226 IP (tos 0x0, ttl 249, id 64067, offset 0, flags [DF], proto TCP (6), length 1280)

ec2-13-228-199-255.ap-southeast-1.compute.amazonaws.com.https > notebookpc.52384: Flags [P.], cksum 0x7334 (correct), seq 12508:13736, ack 782, win 127, options [nop,nop,TS val 3757013568 ecr 318662888], length 1228